Centrifugal separator drive unit and centrifugal separator having replaceable drive unit

Abstract

Centrifugal separator drive unit (6) as an interchangeable drive unit of a centrifugal separator (2) comprising: - a synchronous motor (34) with a sleeve-shaped stator (20) and a rotor (33), wherein a rotatably mounted rotor (21) extends through the sleeve-shaped stator (20) as part of the rotor (33), wherein the rotor (33) comprises a rotating shaft (9) with a terminal shaft end (27) and the rotor (21) attached to the rotating shaft (9), - one or more rotating shaft bearings (17, 18) as part of the rotor (33);and - a housing unit (32) in which the synchronous motor (34) is arranged, wherein a cooling line (15) of a liquid cooling device (14) for cooling the stator (20), which is arranged multiple times around the stator (20), is arranged in the housing unit (32) or that the housing unit (32) is designed to provide a cooling line (15) by installing the centrifugal separator drive unit (6) in a receiving housing (7) of a centrifugal separator (6).;

Description

[0001] The present application relates to a centrifugal separator drive unit, a centrifugal separator with an interchangeable drive unit and a method for operating the centrifugal separator.

[0002] Several state-of-the-art documents with different development concepts are known.

[0003] German patent application DE 10 2017 114 649 A1 discloses an interchangeable drive unit in a centrifugal separator. The complete drive unit consists, among other things, of a stator of an electric motor mounted in a sleeve, as well as a rotor with a corresponding drive spindle and a lower and upper bearing. The bearings are held in the sleeve, so that these components are assembled into a drive cassette. For repair or maintenance purposes, the cassette can be disassembled and replaced as a complete unit. The cassette has a shoulder / recess, which in turn is mounted on a shoulder / recess inside the separator housing. The height of the drive unit can be changed and adjusted using simple spacers inserted between these two shoulders. This may be necessary to precisely adjust the position of the rotating gripper chamber relative to the stationary gripper.Unfavorable additive manufacturing tolerances, which can lead to unwanted contact between the gripper and the gripper chamber, are thus easily corrected without the need to rework either component.

[0004] The cassette is fitted into the separator housing in such a way as to ensure excellent heat transfer. To dissipate the heat generated in the motor, the separator housing is equipped with a sufficient number of cooling fins, resulting in a design comparable to a heat sink. The heat is dissipated to the ambient air via convection.

[0005] German patent DE 10 2012 110 846 A1 discloses a direct-drive centrifuge in which the components consisting of the motor, drive spindle, and bearings are not combined in a housing unit to form an interchangeable drive unit. The chamber for the fluid used to cool the motor is integrated into the separator housing.

[0006] EP 4 094 839 A1 discloses a direct-drive centrifuge comprising a multi-component motor, a drive spindle, and a bearing, which are not combined in an interchangeable drive unit. The motor's cooling device is connected to the motor's stator.

[0007] DE 3 922 639 A1 discloses a direct-drive centrifuge in which the components consisting of the motor, drive shaft, and bearings are not combined in a housing or housing unit to form an interchangeable drive unit. The cooling channel is integrated into the motor stand. The inlet and outlet are routed radially from the housing. A feature of this device is the ease of disassembly or replacement of the support bearing and the rotor. Replacing the entire housing is considered a disadvantage.

[0008] Apart from DE 10 2017 114 649 A1 and the concept of motor cooling by means of cooling fins disclosed therein, all other drive concepts mentioned above require the disassembly of the drives. Depending on the concept, the motor cooling is designed in such a way that the coolant must be drained before disassembly.

[0009] Especially in compact drive units, heat is generated in a relatively small space. Heat dissipation through passive cooling is comparatively slow and counteracts the need for a compact drive unit design with high power density.

[0010] Based on this preliminary consideration, the object of the present invention is to provide a drive unit which can be replaced as a whole without prior disassembly and which reduces or completely eliminates the aforementioned disadvantages.

[0011] The invention solves this problem by providing a centrifugal separator drive unit with the features of claim 1.

[0012] A centrifugal separator drive unit according to the invention, as an interchangeable drive unit of a centrifugal separator, comprises a synchronous motor with a sleeve-shaped stator and a rotor, wherein a rotatably mounted rotor extends through the sleeve-shaped stator as a component of the rotor. The rotor further comprises a rotating shaft with a terminal shaft end and the rotor attached to the rotating shaft.

[0013] Furthermore, the centrifugal separator drive unit according to the invention has one or more rotating shaft bearings as a component of the rotor for the rotatable bearing of the rotating shaft.

[0014] The centrifugal separator drive unit also has a housing unit, i.e. a one- or multi-part housing, in which the synchronous motor and thus also the rotating shaft bearing(s) as part of the rotor are arranged.

[0015] In a first embodiment of the invention, a cooling line of a liquid cooling device for cooling the stator is also arranged in the housing unit, which runs several times around the stator.

[0016] In a second embodiment of the invention, the housing unit is designed to provide the cooling line by installing the centrifugal separator drive unit in a receiving housing of a centrifugal separator. This can be achieved in particular by the housing unit having an outer contour, e.g., an externally arranged spiral wall or circular cooling channels, which form a closed cooling line through the wall of the receiving housing.

[0017] Active cooling using a coolant allows for particularly efficient dissipation of the generated heat. Furthermore, unlike passive cooling via cooling fins, the cooling can be adjusted by regulating the flow rate of the coolant, for example, depending on a determined electrical resistance value of the stator winding.

[0018] Advantageous embodiments of the invention are the subject of the dependent claims.

[0019] It is advantageous for the cooling line to be spirally shaped, extending axially beyond the axial length of the stator, such that the stator is cooled along its entire axial circumference by a single cooling medium contained within the cooling line. This circumferential cooling along the entire length of the stator ensures the most uniform heat dissipation possible and effectively reduces heat peaks in specific areas of the stator, particularly at its ends.

[0020] Increased heat generation in the stator can be observed particularly in so-called winding heads. One or more winding heads are arranged at least on one end, preferably on both ends, of the stator and are cooled externally by a cooling line running around the entire stator.

[0021] In one embodiment of the invention, the cooling line can be arranged in a housing wall, preferably in a monolithic housing wall. This embodiment is particularly leak-proof. Alternatively, the housing wall and the cooling line contained therein can be provided by joining two or more housing elements. This allows for very time-efficient mass production, especially in high volumes.

[0022] The rotor of the runner, when configured as a synchronous motor, can incorporate permanent magnets. The assembly or disassembly of such a motor during replacement in the centrifuge, as described in the prior art, necessitates very precise and complex alignment of the components for this type of motor.

[0023] The drive unit can also have an interface for screwing it to the centrifugal separator's mounting housing. For example, the interface can be designed as a flange section.

[0024] The drive unit may also have an interface to a coolant connection for the radial inlet and / or outlet of the coolant from the centrifugal drive unit. For example, the interface may include sealing elements and / or screw threads.

[0025] The cooling line can be designed in a particularly efficient and compact manner by being bifilar. This design also reduces the number of interfaces at the coolant connection and thus the sealing effort.

[0026] The centrifugal separator drive unit can be advantageously encapsulated and / or sealed. This reduces long-term damage to the motor, e.g., during storage, and prevents the ingress of contaminants.

[0027] The housing unit can also have a bottom-side pin section for insertion into a bottom-side receiving contour within the receiving housing. This reduces wobbling of the rotating shaft in the end area.

[0028] The housing unit can also include at least one first lid-shaped housing component and a second sleeve-shaped or housing-cup-shaped housing component with the cooling line or an outer contour for forming the cooling line. In this way, the individual motor components (e.g., stator, rotor) can be arranged very easily and interchangeably within the housing unit.

[0029] The stator can advantageously be designed in a sleeve shape and arranged in a rotationally fixed manner within the second housing component. The first housing component can engage, at least at its ends, with the sleeve shape of the second housing component, preferably by means of a circumferential projection.

[0030] The centrifugal separator drive unit for supporting the rotating shaft can have at least two rotating shaft bearings, arranged axially on both sides of the rotor and fixed to the housing unit. A first rotating shaft bearing can be fixed to the first housing component and a second rotating shaft bearing to the second housing component. The use of two bearings prevents excessive deflection of the rotating shaft in the stator area, thus achieving a constant air gap between the rotor and stator.

[0031] Furthermore, according to the invention, a centrifugal separator comprises a rotatable drum, a cover for the drum, and a bottom-mounted housing with the replaceable centrifugal separator drive unit according to the invention. In the event of a drive failure, the centrifugal separator can be replaced in just a few steps, even by minimally trained personnel. This also simplifies storage. In addition, the weight and volume of the drive unit have been reduced.

[0032] Further advantageous embodiments of the invention are the subject of the dependent claims.

[0033] The centrifugal separator drive unit can advantageously be inserted axially into the bottom-side receiving housing, in particular by plugging it in. This allows for straightforward alignment and centering of the drive unit within the centrifugal separator.

[0034] Preferably, the centrifugal separator drive unit is detachably fixed to the bottom-side receiving housing of the centrifuge.

[0035] Furthermore, the drum can be fixed to the shaft end in a rotationally fixed manner. This shaft end can have a conical end section.

[0036] The centrifugal separator drive unit can be part of a centrifugal separator direct drive. Unlike a wrap-around drive, a direct drive is arranged axially below the drum.

[0037] Furthermore, according to the invention, a method for operating a centrifugal separator according to the invention comprises a replacement of the drive unit, preferably in case of defect, and wherein the replacement comprises the following steps: A. Disassembly of the drum from the shaft end of the drive unit according to the invention; B. Release of a fixing between the receiving housing and the centrifugal separator drive unit; C. Axial removal of the used, preferably defective, drive unit as a unit from the receiving housing and D. Installation of a new drive unit.

[0038] It is advantageous if the flow rate of the coolant conveyed through the cooling line or the coolant temperature is controlled based on a determined electrical resistance value of one or more stator coils. The electrical resistance of the coils correlates with the coil temperature, so that an increase in cooling capacity can be initiated when the temperature rises.

[0039] This control method for operating the centrifuge was previously not possible with a passive cooling device, e.g., using cooling fins.

[0040] The invention is described in more detail below with reference to a preferred embodiment. It shows: Fig. 1 shows a sectional view of a centrifugal separator according to the invention comprising a drive unit according to the invention.

[0041] Fig. 1 Figure 2 shows a centrifuge 2, in particular a centrifugal separator 2 with a rotatably mounted centrifuge drum 1, in particular with a horizontal axis of rotation 100.

[0042] The centrifugal separator 2 can be modified in various ways, for example, to be designed as a self-emptying separator, nozzle separator, disc separator, chamber separator, and / or single-use separator. It can be designed as a two-phase or three-phase separator.

[0043] The centrifuge drum 1 is covered by a hood 3. Furthermore, a collection device for collecting a separated solid phase can be arranged inside the hood, e.g. in a nozzle separator.

[0044] An inlet 4 is arranged axially above the hood 3. A liquid outlet 5 can also be arranged axially above the hood 3. The centrifuge drum 4 is detachably mounted on a rotatably supported shaft end 27 of a rotating shaft 9. This shaft end is preferably conically tapered. This section is described in Fig. 1 covered by the attached centrifuge drum 1.

[0045] The rotating shaft 9 has several different, at least two or more, shaft cross-sections along its axial extent. These serve for positioning and, if necessary, for securing the position by stopping individual components arranged on or around the rotating shaft, such as rotating shaft bearings 17, 18, which may, for example, be designed as rolling bearings.

[0046] The rotating shaft 9 defines a central axis of rotation 100, which also forms the axis of rotation of the centrifuge.

[0047] The rotating shaft 9 is part of a centrifugal separator drive unit 6, hereinafter also referred to as drive unit 6. The drive unit 6 comprises two housing components 11 and 26, which are connected to each other to form a housing unit 32. The connection can be made by a screw connection (not shown).

[0048] Furthermore, the centrifugal separator 2 has a mounting housing 7 for receiving the drive unit 6. The hood 3 of the centrifugal separator 2 is in Fig. 1 connected to the receiving housing 7, preferably by means of adjacent flange surfaces.

[0049] The receiving housing 7 has at least in some areas one or more receiving contours 10 corresponding to one or more of the housing components. The receiving contour 10 is located on the bottom side of the receiving housing 7. It allows for the axial insertion of an end pin section 29 of the drive unit 6 into the receiving contour 10.

[0050] Radially to the axis of rotation 100, a first coolant connection 8a for the supply and a second coolant connection 8b for the coolant discharge are arranged on the housing unit 32 within the receiving housing 7. The supply and discharge of the coolant into and out of the cooling line 15 of the liquid cooling device 14 can take place at both axial ends of the liquid cooling device 14 or from only one end. In the case of a bifilar coolant flow (not shown), a crossing of the supply and discharge lines can be avoided.

[0051] The wall of the receiving housing 7 also has a step 30, for the support and stabilization of the drive unit 6 and / or as an axial stop for the insertion depth of the drive unit 6 into the receiving housing 7.

[0052] In the area of ​​step 30, a mechanically releasable fixing 12 is provided between the drive unit 6 and the receiving housing 7, e.g. a screw connection.

[0053] The housing body 26 is designed as a housing cup. The housing cup has the housing pin 29 on its bottom side. This housing pin can have an opening at its axial end, i.e., on its bottom side.

[0054] A synchronous motor 34 with a stator 20 and a rotor 33 with a rotor 21 is arranged within the housing body 26. The stator 20 is rigidly connected, in particular rotationally fixed, to the housing unit of the drive unit 6.

[0055] The housing unit 32, which is in Fig. 1 The housing, which is realized via the housing components 11 and 26, has a wall shell 31. The wall shell 31 can be cylindrical or, if applicable, also designed as a hollow cuboid or as a hollow prism, e.g. with a hexagonal cross-section or the like.

[0056] Within the wall casing 31 of the housing unit 32, a multi-circumferential cooling line 15 is arranged as part of a liquid cooling device 14. The cooling line 15 can be spiral-shaped and serves to convey a cooling medium, in particular cooling water.

[0057] The circumferential cooling in the wall jacket 31 takes place over at least an axial extent which is larger than the axial extent of the stator 20 including the required winding heads.

[0058] In the preferred version of the Fig. 1A first conduit 13 is provided for supplying cooling medium from coolant connection 8a to the circumferential cooling line 15. Furthermore, a second conduit can be provided for draining cooling medium from the cooling line 15 into coolant connection 8b.

[0059] The cooling line 15 is formed by at least one partition 16, e.g. with a spiral course, or by a sequence of several parallel partitions and annular chambers and with connections through the partitions.

[0060] While the cooling line 15 of the liquid cooling device 14 is arranged exclusively in the housing body 26, the line channel 13 and the further line channel extend both partially through the housing body 26 and through the housing body 11.

[0061] The stator 20 contains one or more coil windings 22 made of wound wire, each with axially located winding ends 23 which heat up during operation in the same way as the other coil windings. The axial extension of the cooling line 15 beyond the stator 20 ensures efficient heat dissipation from the winding ends.

[0062] A rotor 21, comprising an arrangement of permanent magnets, is arranged within the rotationally fixed stator 20. The rotor 21 is arranged along a rotating shaft 9. The rotor 21, the rotating shaft 9, and the rotating shaft bearings 17, 18 are components of the rotor 33 of the synchronous motor 34.

[0063] The rotating shaft bearings 17 and 18 are arranged axially on both sides of the rotor 21. The rotating shaft bearings 17 and 18 for supporting the rotating shaft 9 are arranged within the housing unit 32.

[0064] The lower rotating shaft bearing 18 is also held in the hollow housing pin 29 on the bottom side of the housing cup-shaped housing body 26. The upper rotating shaft bearing 17 is mounted in the housing body 11, which is designed as a flange-like cover. The housing body 26 is thus closed at the top, so that all these housing components are assembled to form the drive unit 6. For repair or maintenance purposes of the centrifugal separator 2, the drive unit can be disassembled and replaced as a complete unit. Preferably, the drive unit 6 can be encapsulated externally and, more preferably, sealed. This arrangement of a complete drive unit 6 is particularly advantageous in electric motor drives in which, as described above, strong permanent magnets are installed in a rotor, such as in synchronous motors.Since the cassette is replaced as a complete drive unit, the guidance of the magnetic flux remains within the drive unit 6 and does not act externally.

[0065] The liquid cooling device 14, preferably the channel-shaped cooling line 15 in the housing wall 31 of the housing unit 32, achieves particularly efficient cooling of the electric motor and an increase in its power density.

[0066] As an alternative to the depicted form, the housing body 26 can also be manufactured in two parts, with an inner sleeve and an outer sleeve, wherein the inner sleeve is provided with one or more open channels on its outer circumference. The open spiral channel is then closed by an outer sleeve. This allows the housing body 26 to be manufactured in a straightforward manner using material-removing manufacturing processes, e.g., milling, whereby the contour of the cooling line 15 is milled out on the outer circumference of the sleeve. Alternatively, it can also be manufactured simply by casting.

[0067] Alternatively, the housing element 26 can be sleeve-shaped or cup-shaped and simultaneously formed as a single piece. An open channel can be formed on the outside of the single-piece sleeve. When the drive unit 6, and thus the housing element 26, is inserted into the receiving housing 7 of the centrifugal separator 2, the open channel(s) are closed by the housing wall of the receiving housing 7, forming a corresponding cooling line with a similar path to the cooling line 15.

[0068] Together with the receiving housing 7, this results in the cooling line preferably with interface to corresponding coolant connections 8a and 8b and the line channels, e.g. a corresponding line channel 13, which are also formed by both housings 7 and 26.

[0069] The housing unit 32, in particular the housing element 26, is mechanically connected to the stator 20 of the synchronous motor 34 in such a way that very good heat transfer is ensured. To dissipate the power loss generated in the synchronous motor 34, the cooling fluid, in particular water, is continuously pumped through the liquid cooling device 14.

[0070] If the discharged heated coolant is cooled again by means of a heat exchanger outside the drive unit 6, it can be used continuously in this cooling circuit.

[0071] The supply and return lines to the cooling line 15 are guided into the flange-like lid-shaped housing body 11 of the drive unit 6 and from there axially in the housing unit 32.

[0072] Alternatively, one or more cooling lines 15 can also be arranged within the housing unit 32, in particular within the housing body 26, so that they can be closed and implemented without the surrounding receiving housing 7.

[0073] For example, such a housing unit with an internal cooling line can be manufactured using 3D printing, or a spiral line can be cast into the housing body 26.

[0074] In addition to a classic spiral design of the cooling line 15, it can also be designed bifilarly, as previously explained. In this configuration, the spiral cooling line 15 is designed with two turns, with the coolant supply channel and the coolant discharge channel running into each other. A corresponding design of such a cooling line is shown in DE 1 613 014 A1. Such a bifilar winding has the following advantages: Since the cooler incoming fluid and the warmer outgoing fluid are constantly in contact, the resulting housing temperature is very uniform and almost constant.

[0075] Furthermore, the inlet and outlet can be arranged at the same end of the housing unit 32 of the drive unit 6 without these lines crossing. Reference sign

[0076] 1 Drum 2 Centrifugal separator 3 Hood 4 Supply line 5 Liquid drain 6 Centrifugal separator drive unit 7 Mounting housing 8a, 8b Coolant connection 9 Rotating shaft 10 Mounting contour 11 Housing body 12 Fixing 13 Cable channel 14 Liquid cooling device 15 Cooling line 16 Partition 17 Rotating shaft bearing 18 Rotating shaft bearing 20 Stator 21 Rotor 22 Coil windings 23 Winding heads 26 Housing body 27 Shaft end 29 Housing journal 30 Stepping 31 Wall jacket 32 ​​Housing unit 33 Rotor 34 Synchronous motor 100 rotary axis

Claims

1. Centrifugal separator drive unit (6) as an interchangeable drive unit of a centrifugal separator (2) comprising: - a synchronous motor (34) with a sleeve-shaped stator (20) and a rotor (33), wherein a rotatably mounted rotor (21) extends through the sleeve-shaped stator (20) as part of the rotor (33), the rotor (33) comprising a rotating shaft (9) with a terminal shaft end (27) and the rotor (21) attached to the rotating shaft (9); - one or more rotating shaft bearings (17, 18) as part of the rotor (33); and - a housing unit (32) in which the synchronous motor (34) is arranged. characterized by the fact thata cooling line (15) of a liquid cooling device (14) for cooling the stator (20), which is arranged several times around the stator (20), is arranged in the housing unit (32) or that the housing unit (32) is designed to provide a cooling line (15) by installing the centrifugal separator drive unit (6) in a receiving housing (7) of a centrifugal separator (6).

2. Centrifugal separator drive unit according to claim 1, characterized by the fact that the cooling line (15) is spirally shaped, the spiral cooling line (15) extending in the axial direction beyond the axial extent of the stator (20) in such a way that the stator (20) is cooled over its entire axial extent along the outer circumference by a cooling medium guided in the cooling line (15).

3. Centrifugal separator drive unit according to claim 1 or 2, characterized by the fact thatthe stator (20) has at least one-sided, preferably both-sided terminal winding heads (23) which are cooled on the outside around the stator (20) by the cooling line (15).

4. Centrifugal separator drive unit according to one of the preceding claims, characterized by the fact that the cooling line (15) is arranged in a wall jacket (31), preferably in a monolithic housing wall, or that it is provided by joining two housing elements.

5. Centrifugal separator drive unit according to one of the preceding claims, characterized by the fact that the rotor (21) has permanent magnets.

6. Centrifugal separator drive unit according to one of the preceding claims, characterized by the fact that the drive unit (6) has an interface as a fixing (12) with the receiving housing (7) of the centrifugal separator (2).

7. Centrifugal separator drive unit according to one of the preceding claims, characterized by the fact thatthe drive unit (6) has an interface to a coolant connection (8a, 8b) for radial inlet and / or outlet of the coolant from the centrifugal drive unit (6).

8. Centrifugal separator drive unit according to one of the preceding claims, characterized by the fact that the cooling line (15) is bifilar in design.

9. Centrifugal separator drive unit according to one of the preceding claims, characterized by the fact that the housing unit (32) has a bottom housing pin (29) for insertion into a bottom receiving contour (10) inside the receiving housing (7).

10. Centrifugal separator drive unit according to one of the preceding claims, characterized by the fact thatthe housing unit (32) has at least a first lid-shaped housing component (11) and a second sleeve-shaped or housing-cup-shaped housing component (26) with the cooling line (15) or an outer contour, in particular a radial partition (16), for forming the cooling line (15).

11. Centrifugal separator drive unit according to one of the preceding claims, characterized by the fact that the stator (20) is designed in a sleeve shape and is arranged in a rotationally fixed manner in the second housing component (26).

12. Centrifugal separator drive unit according to one of the preceding claims, characterized by the fact thatthe centrifugal separator drive unit (6), in particular the rotor (33), has two rotating shaft bearings (17, 18) for supporting the rotating shaft (9), which are arranged axially on both sides of the rotor (21) and which are fixed to the housing unit (32), wherein a first rotating shaft bearing (17) is fixed to the first housing part (11) and a second rotating shaft bearing (18) is fixed to the second housing part (26).

13. Centrifugal separator (2) comprising a rotatable drum (1), a hood (3) for covering the drum (1) and a bottom-mounted receiving housing (7) with an interchangeable centrifugal separator drive unit (6) according to one of the preceding claims.

14. Centrifugal separator according to claim 13, characterized by the fact that the centrifugal separator drive unit (6), as a whole removable unit, is axially inserted, in particular plugged into, the bottom-side receiving housing (7).

15. Centrifugal separator according to any one of the preceding claims, characterized by the fact that the drum (1) is non-rotatably connected to the shaft end (27) and is preferably part of a centrifugal separator direct drive.

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