Magnetic coupling pump assembly having spacer tank and method for manufacturing spacer tank

Abstract

The invention relates to a magnetically coupled pump assembly, comprising: an interior space (11) formed by a pump housing (2) of the pump assembly; a spacer tank (10) with a central longitudinal axis (B), said spacer tank tightly sealing a chamber (12) surrounded by the spacer tank from an interior space (11) formed by the housing (2); an impeller shaft (13) rotatably drivable about an axis of rotation (A); an impeller (16) arranged at one end of the impeller shaft (13); an inner rotor (17) arranged at the other end of the impeller shaft (13); and an outer rotor (24) arranged on the drive shaft (20) and interacting with the inner rotor (17). According to the invention, the outer peripheral surface (31) of the spacer tank (10) is provided with a plurality of projections (32, 32 ').

Description

Technical Field

[0001] This invention relates to a magnetically coupled pump assembly comprising: an internal space formed by a pump housing of the pump assembly; a spacer (or isolation tank, i.e., a spalttopf) with a central longitudinal axis, the spacer tightly sealing the chamber it surrounds relative to the internal space formed by the housing; an impeller shaft rotatably driven about a rotation axis; an impeller disposed at one end of the impeller shaft; an inner rotor disposed at the other end of the impeller shaft; and an outer rotor disposed at a drive shaft and acting in conjunction with the inner rotor. The invention also relates to a method for manufacturing the spacer of such a magnetically coupled pump assembly. Background Technology

[0002] These sealless pumps are particularly useful for conveying hazardous or toxic media in order to eliminate leaks, because, depending on the medium, even small amounts of the conveyed medium can have life-threatening consequences.

[0003] In the case of shaftless pumps, especially magnetically coupled pumps, the spacer tank constitutes a weak point because it is implemented with the smallest possible wall thickness based on performance losses and torque transmission. A problem with conventional spacers is that their condition cannot be monitored or can only be monitored in a limited way. For example, if impurities are present in the pumped medium, the spacer tank may wear through, and potentially hazardous media may flow into so-called lampshade-shaped components or the bearing housings of the outer rotor.

[0004] Typically, or in conventional solutions, a leak monitoring device in the form of a level gauge is installed in the area of ​​the lampshade-shaped component / bearing housing. The problem here is that at least the areas in the lampshade-shaped component and bearing housing become contaminated, posing a potential hazard. Furthermore, this solution cannot rule out the possibility of the transported medium escaping through the support. Therefore, a secondary protective sleeve cannot be used in this case.

[0005] The secondary protective sleeve is achieved, for example, by using a second spacer tank, which is mounted on top of the first spacer tank and statically sealed. The intermediate region between the spacer tanks can be monitored using different sensors.

[0006] There are currently two variations when using a second spacer. As known from EP0286822A2, a metal spacer is used as the primary protective sleeve, combined with a ceramic spacer mounted on top as the secondary protective sleeve. The problem here is the resulting total thickness of the two spacers, as the ceramic spacer requires a higher wall thickness to withstand pressure. In this variation, no additional eddy current losses are generated, but the problem is that with the increased wall thickness, the transmittable torque decreases compared to a single-walled spacer. To compensate for this, a larger magnetic coupler must be installed, which, combined with the more expensive ceramic spacer, leads to high costs. Furthermore, ceramic is a brittle material and may fail suddenly under mechanical loads.

[0007] The second variation uses two spacer tanks stacked on top of each other, as known from WO2014 / 032816A1. Here, the resulting intermediate gap is monitored by means of a sensing device, as in the previous variation.

[0008] The problem here is that eddy currents are induced in the metal / conductive material / spacer tank due to magnetic coupling, which manifest as heat due to the material's resistance. The first negative aspect is increased eddy current losses and therefore lower pump efficiency. The second negative point is that the heat generated in the second spacer tank can only be transferred with difficulty or only to a limited extent to the inner spacer tank, where the heat is output to the conveyed medium. This causes the outer spacer tank to continue heating up, which can lead to expansion and wear at the outer rotor. On the other hand, the high temperature limits the applicability of magnetically coupled pumps because the high surface temperature negatively impacts explosion-proof safety (ATEX rating). For these reasons, double-walled spacers made of metal are classified as impractical and only suitable for limited use.

[0009] One solution to the previously listed problems is known from WO 2020 / 212250A1, in which a spacer for a magnetic coupler is provided with a columnar one-piece cover region and a bottom region connected to a first end of the cover region, wherein at least the cover region has an inner wall portion and an outer wall portion surrounding the inner wall portion, wherein the inner wall portion and the outer wall portion are spaced apart from each other in the radial direction via a gap, and the inner wall portion is integrally connected to the outer wall portion via a plurality of tabs. Summary of the Invention

[0010] The objective of this invention is now to provide a pump assembly, particularly a magnetically coupled pump assembly, in which eddy current losses within the spacer tank are minimized without compromising the stability of the spacer tank.

[0011] The objective of this invention is achieved by providing multiple protrusions on the outer peripheral surface of the spacer (especially the base and bottom), thereby reducing eddy current losses and making the spacer heat up less intensely.

[0012] It has proven particularly advantageous that the protrusions are at least partially inclined. Due to the inclined arrangement of the protrusions, the resulting losses and temperatures are further reduced.

[0013] In a further design, a channel-like hollow space extends through the protrusion, allowing the spacer located at the housing or at a component associated with the housing (e.g., a housing cover) to be inspected for leaks. These hollow spaces may have a defined internal pressure, i.e., positive or negative pressure. The hollow spaces may be under vacuum or filled with gas. If some portion of the protrusion is damaged, resulting in damage to the outer side of the spacer, sensors monitoring the hollow spaces detect that the vacuum is no longer present or that gas is escaping from the hollow spaces. In the case of damage to the inner side of the spacer, sensors detect that the channel is filled with the transported medium. In both cases, pump shutdown is possible.

[0014] Therefore, in both cases, the transported medium has not escaped into the lampshade-shaped component area. This translates to a significantly improved level of safety for this type of magnetically coupled pump assembly. The protrusions and hollow spaces extend both in the body region of the spacer tank base and in the region at the bottom of the spacer tank.

[0015] Advantageously, the shape of the hollow space substantially corresponds to the shape of the protrusion, wherein the protrusion or hollow space can be constructed as a triangle, ellipse, circle, semi-ellipse, semi-circle, trapezoid, or other polygonal design. By adapting the appropriate geometry to the corresponding needs, the resulting losses and temperatures are significantly reduced.

[0016] The protrusion is constructed in a threaded or spiral shape relative to the centerline of the spacer tank in such a way that the protrusion is arranged obliquely relative to an imaginary line extending parallel to the central longitudinal axis of the spacer tank on the outer circumferential surface, wherein the protrusion and the line L enclose an angle in the range of greater than 0° and less than 90°, thereby allowing powdery material remaining in the hollow space during manufacturing to be removed from the channel.

[0017] Advantageously, the angle range is between 30° and 70°.

[0018] It has been shown that the clamping angle is between 40° and 55°. This results in a reduction in the weight of the spacer, a decrease in electromagnetic losses, and particularly good heat dissipation during operation.

[0019] In another advantageous design, the inclined, elongated protrusions are interrupted by a plurality of axially extending protrusions, wherein a channel-like hollow space extends through the axial protrusions and is connected to the hollow spaces of the inclined, elongated protrusions. This further reduces electromechanical losses; moreover, during the manufacture of the spacer, metal powder remaining in the channel-like hollow space during 3D printing can be easily removed from the channel.

[0020] In another advantageous design of the spacer tank, the protrusion has an axially extending section at at least one end region. The advantage here is that the hollow spaces in the base and bottom of the spacer tank can be better interconnected.

[0021] Here, in a special design, the obliquely extending protrusions between axial sections undergo a reversal of direction approximately at the center of the matrix, thus creating a substantially mirror-symmetrical orientation of the protrusions. The advantage of this is that powder within the hollow space can be removed from the channel via a shorter path during manufacturing.

[0022] According to the method of the present invention, the outer peripheral surface of the spacer is provided with a plurality of protrusions.

[0023] To achieve the defined and desired organizational structure, it is preferable to manufacture the spacer can by means of a method in which a spacer can with protrusions and hollow spaces is produced by selectively applying an energy beam to layers of powder applied layer by layer. Attached Figure Description

[0024] Embodiments of the present invention are shown in the accompanying drawings and described in more detail below. Wherein: Figure 1 A longitudinal section of a magnetically coupled pump assembly according to the prior art is shown; Figure 2 A three-dimensional illustration of a first embodiment of the spacer according to the present invention is shown in enlarged view; Figure 3 Showing according to Figure 2 A side view of the spacer tank according to the present invention; Figure 4 Showing according to Figure 2 The segment of the spacer according to the present invention; Figure 5 A section of the spacer according to the invention is shown, according to another embodiment of the spacer. Figure 6 A section of the spacer according to the invention is shown, according to another embodiment of the spacer. Figure 7 A side view of a spacer tank according to another embodiment of the invention is shown; Figure 8 Showing according to Figure 7 The segment of the spacer according to the present invention; Figure 9 A partial view showing another embodiment of the spacer tank; Figure 10 A schematic diagram showing another embodiment of the spacer tank according to the present invention is shown; Figure 11 A schematic diagram showing another embodiment of the spacer tank according to the present invention is shown; Figure 12 Showing according to Figure 1 First view of the hollow space outline of the spacer tank; Figure 13 Showing according to Figure 1 A second view of the hollow space outline of the spacer tank. Detailed Implementation

[0025] Figure 1 An exemplary pump assembly 1 is shown in the form of a magnetically coupled pump assembly as known in the prior art. The pump assembly 1 has a multi-piece pump housing 2 of a centrifugal pump, which includes a hydraulic housing 3 configured as a helical shell, a housing cover 4, a bearing seat lampshade-shaped component 5, a bearing seat 6, and a bearing cover 7.

[0026] The hydraulic housing 3 has an inlet opening 8 for drawing in the conveying medium and an outlet opening 9 for discharging the conveying medium. A housing cover 4 is disposed on the side of the hydraulic housing 3 opposite to the inlet opening 8. A bearing housing lampshade-shaped component 5 is fixed to the side of the housing cover 4 away from the hydraulic housing 3. A bearing housing 6 is disposed on the side of the bearing housing lampshade-shaped component 5 opposite to the housing cover 4. A bearing cover 7 is also fixed to the side of the bearing housing 6 away from the bearing housing lampshade-shaped component 5.

[0027] The spacer 10 is fixed to the side of the housing cover 4 opposite to the hydraulic housing 3 and extends at least partially through the internal space 11 defined by the pump housing 2, especially by the housing cover 4, by the bearing housing lampshade-shaped component 5, and by the bearing housing 6. The spacer 10 tightly seals the chamber 12 it surrounds relative to the internal space 11.

[0028] An impeller shaft 13, which can rotate about the rotation axis A, extends from a flow chamber 14, which is limited by a hydraulic housing 3 and a housing cover 4, through an opening 15 provided in the housing cover 4, into the chamber 12.

[0029] An impeller 16 is fixed at the shaft end of the impeller shaft 13 located within the flow chamber 14, and an inner rotor 17 arranged within the chamber 12 is arranged at the opposite shaft end. The inner rotor 17 is equipped with a plurality of magnets 18, which are arranged on the side of the inner rotor 17 facing the spacer tank 10.

[0030] A bearing assembly 19 is arranged between the impeller 16 and the inner rotor 17 and is operatively connected to the impeller shaft 13, which is rotatably driven around the rotation axis A.

[0031] A drive motor (preferably an electric motor), not shown, drives the drive shaft 20. The drive shaft 20, rotatable about a rotation axis A, is substantially coaxial with the impeller shaft 13. The drive shaft 20 extends through the bearing cover 7 and the bearing housing 6 and is supported by two ball bearings 21 and 22 housed in the bearing housing 6. An outer rotor 24 carrying a plurality of magnets 23 is arranged at the free end of the drive shaft 20. The magnets 23 are arranged on the side of the outer rotor 24 facing the spacer tank 10. The outer rotor 24 extends at least partially over the spacer tank 10 and interacts with the inner rotor 17, such that the rotating outer rotor 24, by means of magnetic force, also puts the inner rotor 17 into rotational motion, and thus puts the impeller shaft 13 and the impeller 16 into rotational motion.

[0032] exist Figure 2 and Figure 3 The spacer tank 10, presented in a magnified view, is configured for mounting to various magnetically coupled pump assemblies, exemplarily in... Figure 1 In the pump assembly 1 shown, the spacer tank 10 has a substantially columnar base 25, the base having a shape consistent with that of the pump assembly 1 shown in the figure. Figure 1 The rotation axis A is substantially coaxial with the central longitudinal axis B. The base 25 is open on one side and closed on the opposite side by means of a substantially arched bottom 26. An annular connecting flange 27 is arranged on the open side, which is integrally constructed with the base 25.

[0033] The connecting flange 27 has a plurality of holes 28 extending parallel to the central longitudinal axis B, through which threaded parts (not shown) can be plugged and screwed into according to... Figure 1 In the corresponding threaded hole in the housing cover 4.

[0034] The bottom 26 consists of a generally spherical fan-shaped intercepting region 29 and an outer edge region 30 that forms a transition region between the base 25 and the intercepting region 29.

[0035] Such as combination Figure 3 and Figure 4As can be seen, the substrate 25 has an outer peripheral surface 31 with a plurality of protrusions 32. The outer peripheral surface 31 is substantially wavy, with a plurality of corresponding crests 33 and troughs 34. The protrusions 32 are configured in a threaded or spiral shape, that is, the protrusions 32 are arranged obliquely relative to an imaginary line L extending parallel to the central longitudinal axis B on the outer peripheral surface 31. In the illustrated embodiment, the protrusions 32 and the line L enclose an angle α of 45°. The angle α can move in a range greater than 0° up to less than 90°. Preferably, the angle α is in the range of 30° to 70°. A channel-like hollow space 35 extends through the protrusions 32.

[0036] Figure 4 The image shows a triangular protrusion 32 with a triangular hollow space 35; while Figure 5 The diagram shows an elliptical protrusion 32 with an elliptical hollow space 35, constructed on the outer peripheral surface 31 of the spacer 10. Other designs for the protrusion 32 are feasible. These protrusions can have a semi-circular or semi-elliptical design, such as... Figure 6 As shown in the diagram, or it can have a trapezoidal or other polygonal design scheme.

[0037] Figure 7 Combination Figure 8 Another embodiment of the spacer tank 10 for use in a magnetically coupled pump assembly is shown. In the illustrated embodiment, an obliquely extending protrusion 32 constructed on the base 25 is interrupted by a plurality of protrusions 32' extending in an axial direction (i.e., parallel to the central longitudinal axis B). A channel-like hollow space 35' extends through the axial protrusions 32', and the hollow space communicates with the hollow space 35 of the obliquely extending protrusions 32. The design of the protrusions 32' may correspond to the design of the protrusions 32; however, it is also conceivable that the designs of the protrusions 32 and 32' may differ.

[0038] Figure 9 Another variation of the spacer tank 10 is shown. An inclined, extending protrusion 32 extends from one protrusion 32' parallel to the central longitudinal axis B of the spacer tank 10 toward another protrusion 32' parallel to the central longitudinal axis B of the spacer tank 10, extending at a specific angle α relative to an imaginary line L on the outer peripheral surface 31, parallel to the central longitudinal axis B. Subsequent protrusions 32 extending from the protrusion 32' are arranged at an angle α' relative to the line L, the angle α' essentially corresponding to 360°−α, thus producing a herringbone-like design.

[0039] Figure 10Another design for the protrusion 32 on the outer peripheral surface 31 of the spacer is schematically shown. The protrusion 32 may have axially extending (i.e., parallel to the axis of rotation A) sections 38 or 39 at at least one end region 36, 37, wherein these sections also have channel-shaped hollow spaces as described in the foregoing figures. The shape of the protrusion 32 or the hollow space can be chosen accordingly.

[0040] Figure 11 Another alternative design for the protrusion 32 is schematically shown. The obliquely extending protrusion 32, extending between axial sections, undergoes a reversal of direction approximately at the center of the base 25, thus creating a substantially mirror-symmetrical orientation for the protrusion 32. Here, the axial sections 38 and 39 of the protrusion 32 are substantially located in a single plane. It can be seen that the axial sections can be omitted, and the protrusion 32 can have a relatively... Figure 3 The hypothetical line L shown in the diagram has a sloping direction.

[0041] The described implementation shows that the spacer tank is constructed as a uniform component. It is manufactured using 3D printing methods.

[0042] Figure 12 Combination Figure 13 The hollow space outline or orientation of the hollow space 35 in the spacer tank 10 is shown, especially according to Figure 2 or Figure 3 The surface of the hollow space. The metallic material is, to some extent, concealed. It can be seen that an annular space 40 is constructed on the side of the substrate 25 opposite to the open side. From this annular space, the hollow space 35 extends towards the open side and ultimately connects to either the first semi-annular hollow space 41 or the second semi-annular hollow space 42. The first connecting channel 43 extends from the first semi-annular hollow space 41 through... Figure 2 The connecting flange 27 is shown. The first connecting channel 43 is also present. Figure 1 As shown in the diagram, the second connecting channel 44 extends from the second hollow space 42 of the semi-annular structure through the connecting flange 27.

[0043] As from Figure 13 As can be seen, the first hollow space 41 of the semi-annular structure has a first sloping region with an inclined portion 45 and a second sloping region with an inclined portion 46, which converge at a point 47. The second hollow space 42 of the semi-annular structure has a first sloping region with an inclined portion 48 and a second sloping region with an inclined portion 49, which converge at a point 50.

[0044] When the open side of the spacer is oriented downwards, the first connecting channel 43 and the second connecting channel 44 are arranged at the lowest part of the hollow space 41 or the hollow space 42.

[0045] Therefore, it is feasible that loose powder remaining in the hollow spaces 35, 35', 40, 41 and 42 during 3D printing manufacturing can flow out from the region of the bottom 26 through the region of the substrate 25 and through the region of the connecting flange 27 and finally through the first connecting channel 43 or the second connecting channel 44, or it can be removed from these hollow spaces by blowing.

Claims

1. A magnetically coupled pump assembly, comprising: -The internal space (11) formed by the pump housing (2) of the pump assembly; - A spacer tank (10) with a central longitudinal axis (B) that tightly seals the chamber (12) surrounded by the spacer tank relative to the internal space (11) formed by the pump housing (2); - An impeller shaft (13) that can be rotatably driven about the axis of rotation (A); - An impeller (16) is arranged at one end of the impeller shaft (13); - An inner rotor (17) is arranged at the other end of the impeller shaft (13); - An outer rotor (24) arranged at the drive shaft (20) and acting in conjunction with the inner rotor (17), Its features are, The outer peripheral surface (31) of the spacer (10) is provided with a plurality of protrusions (32, 32').

2. The magnetic coupling pump assembly according to claim 1, characterized in that, The outer peripheral surface (31) of the spacer (10) is provided with a plurality of protrusions (32, 32'), and the protrusions are at least partially inclined.

3. The magnetic coupling pump assembly according to claim 1 or 2, characterized in that, A channel-shaped hollow space (35, 35') extends through the protrusion (32, 32').

4. The magnetic coupling pump assembly according to claim 3, characterized in that, The shape of the hollow space (35, 35') substantially corresponds to the shape of the protrusion (32, 32'), wherein the protrusion (32, 32') or the hollow space (35, 35') is constructed in the form of a triangle, ellipse, circle, semi-ellipse, semi-circle, trapezoid, or other polygonal design.

5. The magnetic coupling pump assembly according to any one of the preceding claims, characterized in that, The protrusion (32) is configured in a threaded or spiral shape.

6. The magnetic coupling pump assembly according to any one of the preceding claims, characterized in that, The protrusion (32) is arranged obliquely relative to an imaginary line (L) extending parallel to the central longitudinal axis (B) on the outer peripheral surface (31), wherein the protrusion 32 and the line L enclose an angle (α) in the range of greater than 0° and less than 90°.

7. The magnetic coupling pump assembly according to claim 6, characterized in that, The angle (α) is in the range of 30° to 70°.

8. The magnetically coupled pump assembly according to claim 6 or 7, characterized in that, The angle (α) is 45°.

9. The magnetic coupling pump assembly according to any one of the preceding claims, characterized in that, The inclined protrusion (32) is interrupted by a plurality of protrusions (32') extending in the axial direction.

10. The magnetic coupling pump assembly according to any one of the preceding claims, characterized in that, A channel-shaped hollow space (35') extends through the axial protrusion (32'), and the channel-shaped hollow space (35') communicates with the hollow space (35) of the inclined protrusion (32).

11. The magnetic coupling pump assembly according to any one of the preceding claims, characterized in that, The protrusion (32) has an axially extending section (38, 39) at at least one end region (36, 37).

12. The magnetic coupling pump assembly according to any one of the preceding claims, characterized in that, The protrusions (32) that extend obliquely between axial sections undergo a reversal of direction at approximately the center of the base (25), thus giving the protrusions (32) a substantially mirror-symmetrical orientation.

13. A method for manufacturing a spacer tank for a magnetically coupled pump, characterized in that, The outer peripheral surface (31) of the spacer (10) is provided with a plurality of protrusions (32, 32').

14. The method according to claim 13, characterized in that, The spacer can (10) is manufactured by selectively applying an energy beam to a layer of powder applied layer by layer, thereby producing the spacer can with the protrusions (32, 32') and the hollow space (35, 35').

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