Coupling unit with thermal separation effect

Abstract

The invention relates to a pump assembly having a coupling unit (1). The coupling unit (1) connects a pump casing (3) to a motor casing (7). Arranged within the coupling unit (1) is at least one thermal barrier (12).

Description

[0001] The invention relates to a pump arrangement with a lantern that connects a pump housing and a motor housing.

[0002] One such pump arrangement could be, for example, a centrifugal pump arrangement. Centrifugal pumps are based on the operating principle of energy transfer to a fluid through a change in swirl caused by a torque exerted on the fluid flowing through it by a uniformly rotating impeller.

[0003] Centrifugal pumps are most often driven by electric motors. Besides electric drives, piston engines are also used in centrifugal pump technology. Electric motors generate a constant torque. An electric motor is an electromechanical energy converter that transforms electrical energy into mechanical energy. Depending on the form in which the electrical energy is available, DC, AC, or three-phase motors are used. Generally, the electrical energy is converted into rotational motion.

[0004] The electric motor driving a centrifugal pump is usually connected to the pump at a specific distance via a lantern. The motor drive shaft passes through openings in the center of the two flanges or covers for mounting to the motor and the pump housing. Lanterns are typically manufactured by casting.

[0005] Such a lantern and a corresponding manufacturing process are described, for example, in EP 1 038 611 A2. The type and number of connecting webs described enable a particularly stable lantern design.

[0006] US 4,720,248 A describes a wet rotor circulating pump and motor assembly comprising a pump with a casing, a motor with a casing, and a thermal barrier arranged between the pump casing and the motor casing, wherein the barrier includes a removable second section comprising a plurality of separable components and designed to impede heat transfer and transmit stresses between the casings.

[0007] EP 0 879 967 B1 discloses a machine assembly with a thermal barrier in which a hot part and a cool part have adjacent flange-like plates spaced apart from each other, which are connected to each other via one or more force-transmitting metallic elements, the connection being made via a minimum cross-sectional area sufficient for force transmission, and the two flange-like plates being connected to each other by a tubular body.

[0008] US 5 624 245 A discloses a high-temperature liquid pump with a thermal insulator arranged between a pump casing and a sealing casing, spacing the casings apart to reduce heat transfer from the pump casing to the sealing casing.

[0009] In pump systems used to transfer fluids at high temperatures, significant heat can be transferred from the pump housing towards the electric motor. This can lead to several problems with the electric motor. High temperatures reduce the efficiency of energy conversion. The motor components, especially the stator and rotor windings, are subjected to thermal stress, which can shorten their service life.

[0010] The electric motor control may reduce the power consumption and speed to prevent the electric motor from overheating, which would prevent the pump from operating within the desired range.

[0011] The object of the invention is to provide a lantern as a connecting element between the pump housing and the drive motor. This connecting element should conduct as little heat as possible from the pump housing towards the motor when pumping hot fluids. Furthermore, the connecting element should be characterized by a compact design. The design of the connecting element should facilitate the replacement of spare parts. The connecting element should be simple and cost-effective to manufacture.

[0012] This problem is solved according to the invention by a pump arrangement with a lantern having the features of claim 1. Preferred variants can be found in the dependent claims, the description and the drawings.

[0013] According to the invention, at least one thermal barrier is arranged within the lantern. Such a thermal barrier is particularly advantageous for thermally decoupling a pump housing, through which a hot fluid flows, from the drive motor. This protects the motor and its components and enables the pump to operate within the desired operating range.

[0014] According to the invention, at least one thermal barrier is arranged in all central axial sections. This achieves thermal decoupling of the pump housing from the motor housing, since heat cannot be conducted via a direct axial connection between the housings.

[0015] According to the invention, such a thermal barrier is designed as a material recess. The space of such a recess is generally occupied by air, which is known to be a particularly good insulator and thus represents a barrier to heat conduction. In an alternative embodiment, which is not covered by the claimed invention, such a thermal barrier could also be designed in the form of a material with particularly poor thermal conductivity, such as a ceramic-based material.

[0016] Preferably, the lantern directly connects the pump housing and the motor housing. In principle, no additional component is necessary to create this connection. Reducing the number of components is usually advantageous for reducing manufacturing costs.

[0017] The lantern is preferably cylindrical and / or trumpet-shaped. This spatial design is particularly advantageous for achieving additional cooling of the lantern by the cooling airflow generated by the motor fan. In an alternative embodiment of the invention, the lantern can also be conical and / or cuboid in shape.

[0018] In one embodiment of the invention, the lantern is formed integrally with the motor-side pressure cover of the pump housing and / or integrally with the pump-side motor cover. Advantageously, this allows the lantern to be designed to be particularly compact and enables a pump arrangement with dimensions that can also be used in installation locations with limited space.

[0019] Preferably, the thermal conductivity of the lantern material is less than 400 W / m·K, preferably less than 300 W / m·K, in particular less than 250 W / m·K, and / or more than 10 W / m·K, preferably more than 20 W / m·K, in particular more than 30 W / m·K. The lantern is preferably manufactured from gray cast iron or aluminum using a casting process.

[0020] Ideally, the thermal conductivity of the thermal barrier is less than 20 W / m·K, preferably less than 15 W / m·K, in particular less than 10 W / m·K, and / or more than 0.002 W / m·K, preferably more than 0.05 W / m·K, in particular more than 0.1 W / m·K.

[0021] Preferably, the width of the material recess is more than 0.5 mm, preferably more than 1 mm, in particular more than 1.5 mm, and / or less than 30 mm, preferably less than 25 mm, in particular less than 20 mm. Advantageously, the material thickness of the lantern is more than 1 mm, preferably more than 2 mm, in particular more than 3 mm, and / or less than 14 mm, preferably less than 12 mm, in particular less than 10 mm. The lantern according to the invention is characterized by a slim design with manageable material usage while simultaneously being stable and vibration-resistant.

[0022] Preferably, the lantern is designed as a bearing support on the pump side and / or motor side. This results in a particularly compact design of the lantern and simultaneously reduces assembly effort by decreasing the number of parts.

[0023] The lantern according to the invention is characterized by a compact, axial design in which the entire heat conduction path is extended by the insertion of material recesses.

[0024] Further features and advantages of the invention will become apparent from the description of exemplary embodiments with reference to the drawings and from the drawings themselves.

[0025] This shows: Fig. 1 a section through a centrifugal pump unit, Fig. 2 a perspective view of a lantern, Fig. 3 a perspective view of another lantern design, Fig. 4 a perspective view of a third lantern design, Fig. 5 a perspective view of yet another lantern design.

[0026] Fig. 1 Figure 1 shows a pump arrangement with a lantern 1 connecting a pump housing 3 and a motor housing 7. The centrifugal pump shown in the exemplary embodiment is used for pumping fluids that may have high temperatures.

[0027] The fluid enters the pump housing 3 of the centrifugal pump through a suction port 2. The impeller 4 is located inside the pump housing 3. The impeller 4 transfers kinetic energy to the fluid, which exits the centrifugal pump via the discharge port (not shown in this figure). The space filled with fluid and impeller 4 is bounded by a pump housing 3 and a housing cover 5. The impeller 4 is non-rotatably connected to a shaft 9, which drives the impeller 4 by means of a motor assembly 13. The motor assembly 13 comprises a rotor 10, a stator 8, the shaft 9, a pump-side motor cover 6, and a motor housing 7. A bearing support, which carries a bearing 11, is located in the motor cover 6.

[0028] Based on the illustration of lantern 1 in Fig. 1 It is clearly evident that in all central axial sections a thermal barrier 12 is implemented between the pump housing 3 and the motor housing 7. This thermal barrier 12 is designed such that there is no direct axial connection between the housing parts, which in turn provides greater thermal decoupling between the housings 3 and 7. In this advantageous manner, the radial path of the heat conduction is significantly extended without increasing the axial length of the lantern 1.

[0029] Fig. 2 Figure 1 shows a perspective view of a lantern 1. The connecting plate 15 for connection to the motor cover 6 (not shown) is connected by connecting webs 14 to the connecting plate 16 for connection to the housing cover 5 of the pump housing 3 (also not shown). The lantern 1 has several thermal barriers 12, which, according to the invention, are designed as material recesses. In an alternative embodiment ,The thermal barrier, which is not covered by the claimed invention, could also be made of a material with poor thermal conductivity. The connecting webs 14 prevent interference with the rotating shaft 9. The design of the connecting webs 14 creates a lantern 1 that provides an extremely long thermal conductivity path within the shortest possible axial installation space. The cooling airflow generated by the motor fan (not shown), which flows over the cooling fins of the motor housing 7 towards the lantern 1, can, in addition to the thermal barrier 12, dissipate the heat conducted from the pump housing 3 by the connecting webs 14, so that only a minimal amount of heat reaches the motor cover 6. Due to the particularly advantageous design of the lantern 1, the pump housing 3 and the motor assembly 13 are thermally decoupled to a greater extent.

[0030] Fig. 3 Figure 1 shows a perspective view of another embodiment of the lantern 1. The connecting plate 15 for connection to the motor cover 6 (not shown) is connected by connecting webs 14 to the connecting plate 16 for connection to the housing cover 5 of the pump housing 3 (also not shown). The lantern 1 has several heat-conducting barriers 12, which, according to the invention, are designed as material recesses. In this embodiment of the invention, the connecting webs 14 are designed as cylindrical components, which are integrally formed with the connecting plates 15 and 16 via four small connecting elements. The material recesses are arranged between the small connecting elements, between the cylindrical component and the connecting plate 16, and between the cylindrical component and the connecting plate 15.Advantageously, with this variant of the lantern 1, the motor arrangement 13 is thermally decoupled from the pump housing 3, and at the same time the lantern 1 is designed to be particularly stable and vibration-resistant.

[0031] Fig. 4 Figure 1 shows a perspective view of a third embodiment of the lantern 1 according to the invention. The connecting plate 15 for connection to the motor cover 6 (not shown) is connected by connecting webs 14 to the connecting plate 16 for connection to the housing cover 5 of the pump housing 3 (also not shown). The lantern 1 has a plurality of thermal barriers 12, which, according to the invention, are designed as material recesses. The lantern 1 of Fig. 4 corresponds to lantern 1 from Fig. 3 In addition, the cylindrical component is provided with further axially arranged heat-conducting barriers 12 in the form of material recesses. This extends the radial and / or axial path of the heat conduction from the pump housing 3 towards the motor assembly 13 without increasing the axial length of the lantern 1.

[0032] The thermal conductivity of the lantern material is less than 400 W / m·K, preferably less than 300 W / m·K, particularly less than 250 W / m·K, and / or more than 10 W / m·K, preferably more than 20 W / m·K, particularly more than 30 W / m·K. The thermal conductivity of the thermal barrier 12 is less than 20 W / m·K, preferably less than 15 W / m·K, particularly less than 10 W / m·K, and / or more than 0.002 W / m·K, preferably more than 0.05 W / m·K, particularly more than 0.1 W / m·K.

[0033] The width of the thermal barrier 12, which according to the invention is designed as a material recess, is more than 0.5 mm, preferably more than 1 mm, in particular more than 1.5 mm, and / or less than 30 mm, preferably less than 25 mm, in particular less than 20 mm. The material thickness of the lantern 1 is more than 1 mm, preferably more than 2 mm, in particular more than 3 mm, and / or less than 14 mm, preferably less than 12 mm, in particular less than 10 mm.

[0034] Fig. 5 Figure 1 shows a perspective view of a lantern 1. The connecting plate 15 for connection to the motor cover 6 (not shown here) is connected to the connecting plate 16 for connection to the housing cover 5 of the pump housing 3 (also not shown) via connecting webs 14 and a hollow cylindrical sleeve 17 and further connecting webs 14.

[0035] The lantern 1 has several thermal barriers 12, which, according to the invention, are designed as material recesses. In an alternative embodiment not covered by the claimed invention, the thermal barrier could also be made of a material with poor thermal conductivity. The connecting webs 14 and the hollow cylindrical sleeve 17 prevent engagement with the rotating shaft 9 and transfer the forces from the motor housing 7 to the pump's base, which are exerted by the mass of the motor assembly 13. For this purpose, the hollow cylindrical sleeve 17 is additionally reinforced in the illustrated embodiment by two projections 18.

[0036] The thermal barriers 12, which are arranged next to the connecting webs 14, limit the heat conduction to a minimum and extend the path of the heat conduction from the connecting plate 16 towards the connecting plate 15, in particular through the radially inwardly oriented extension of the connecting webs 14.

[0037] The cuboid connecting plate 16 has rounded corners, with the connecting webs 14 each starting centrally and extending radially inwards like struts. The hollow cylindrical sleeve 17 has additional thermal barriers 12 in the form of material recesses, which lead to a longer heat conduction path and thus thermally decouple the pump housing 3 and the motor housing 7 almost completely.

[0038] The cooling airflow generated by the motor fan (not shown), which flows over the cooling fins of the motor housing 7 towards the lantern 1, can, in addition to the heat conducting barriers 12, dissipate the heat conducted from the pump housing 3 by the connecting webs 14, so that an extremely small amount of heat is transferred to the motor cover 6.

Claims

1. Pump arrangement comprising a lantern (1) which connects a pump casing (3) and a motor casing (7) to each other, wherein at least one thermal barrier (12) is arranged inside the lantern (1), characterized in that at least one thermal barrier (12) is arranged in all central axial sections and the thermal barrier (12) is in the form of a material cutout, the heat not being conducted via a direct axial connection between the pump casing (3) and the motor casing (7).

2. Pump arrangement according to Claim 1, characterized in that the lantern (1) directly connects the pump casing (3) and the motor casing (7).

3. Pump arrangement according to either of Claims 1 and 2, characterized in that the lantern (1) is cylindrical and / or in the form of a trumpet bell and / or conical and / or in the form of a body having a polygonal base face.

4. Pump arrangement according to one of Claims 1 to 3, characterized in that the lantern (1) is formed in one piece with a motor-side pressure cover (5) of the pump casing (3).

5. Pump arrangement according to one of Claims 1 to 4, characterized in that the lantern (1) is formed in one piece with a pump-side motor cover (6).

6. Pump arrangement according to one of Claims 1 to 5, characterized in that the thermal conductivity of the lantern material is less than 400 W / m·K, preferably less than 300 W / m·K, in particular less than 250 W / m·K, and / or more than 10 W / m·K, preferably more than 20 W / m·K, in particular more than 30 W / m·K.

7. Pump arrangement according to one of Claims 1 to 6, characterized in that the thermal conductivity of the thermal barrier (12) is less than 20 W / m·K, preferably less than 15 W / m·K, in particular less than 10 W / m·K, and / or more than 0.002 W / m-K, preferably more than 0.05 W / m-K, in particular more than 0.1 W / m·K.

8. Pump arrangement according to one of Claims 1 to 7, characterized in that the width of the material cutout is greater than 0.5 mm, preferably greater than 1 mm, in particular greater than 1.5 mm, and / or less than 30 mm, preferably less than 25 mm, in particular less than 20 mm.

9. Pump arrangement according to one of Claims 1 to 8, characterized in that the material thickness of the lantern (1) is greater than 1 mm, preferably greater than 2 mm, in particular greater than 3 mm, and / or less than 14 mm, preferably less than 12 mm, in particular less than 10 mm.

10. Pump arrangement according to one of Claims 1 to 9, characterized in that the lantern (1) is in the form of a pressure cover on the pump side and / or in the form of a bearing support on the motor side.

11. Pump arrangement according to one of Claims 1 to 10, characterized in that the displacement distance for the heat conduction is extended beyond a radial deflection by means of at least one portion with an opposing axial displacement distance.

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