Thermal isolation coupling unit

Abstract

The present invention relates to a pump assembly having a coupling unit (1) that connects a pump casing (3) to an electric motor casing (7). At least one thermal barrier (12) is disposed within the coupling unit (1).

Description

[Technical Field]

[0001] The present invention relates to a pump arrangement having a coupling unit connecting a pump housing and an electric motor housing to one another. [Background technology]

[0002] Such a pump design may be, for example, a centrifugal pump design, which operates on the principle that a constant rotation of an impeller exerts a torque on a fluid flowing through the impeller, and that the resulting change in torsion transfers energy to the fluid.

[0003] Centrifugal pumps are often driven by electric motors. In addition to this electric drive, piston-power machines are also used as drive mechanisms in centrifugal pump technology. In this example, the electric motor generates a constant torque. The electric motor is an electromechanical energy converter that converts electrical energy into mechanical energy. Depending on the form in which the electrical energy is available, direct current, alternating current, or three-phase current motors are used. In this example, the electrical energy is usually converted into rotary motion.

[0004] The electric motor that drives a centrifugal pump is usually connected to the pump at a specific interval by a coupling unit. In this example, the motor drive shaft extends through the center of an opening in two flanges or covers that attach to the motor and pump housing. The coupling unit is usually manufactured by casting.

[0005] Such a coupling unit and a corresponding manufacturing method are described, for example, in EP 1 038 611 A2. The type and number of connecting webs described allow for a particularly stable embodiment of the coupling unit.

[0006] Pump designs used to transport high-temperature fluids can experience high heat input from the pump housing toward the electric motor. This high heat input can lead to several problems with the electric motor. High temperatures reduce the efficiency of energy conversion. The motor components, particularly the stator and rotor windings, are thermally stressed, which can shorten their lifespan. The motor controls can potentially reduce power consumption and speed to prevent the motor from overheating, thereby causing the pump to no longer be able to operate within the desired operating range. Summary of the Invention

[0007] The object of the present invention is to provide a coupling unit as a connecting element between a pump housing and a drive motor. This connecting element must minimize the conduction of heat released when conveying hot fluid from the pump housing to the motor. Furthermore, the connecting element must be characterized by a compact construction. Replacement of exchangeable components must be facilitated by the construction of the connecting element. The connecting element must be capable of being manufactured in a simple and cost-effective manner.

[0008] This object is achieved according to the invention by a pump arrangement having a coupling unit with the features of claim 1. Preferred variants can be derived from the dependent claims, the description and the drawings.

[0009] According to the invention, at least one thermally conductive barrier is arranged inside the coupling unit. Such a thermally conductive barrier is particularly advantageous for thermally decoupling the pump housing, through which the hot fluid flows, from the drive motor. This thermally conductive barrier protects, among other things, the motor and the components mounted therein, and also ensures operation of the pump in the desired operating range.

[0010] Ideally, at least one heat-conducting barrier is located in every central axial section, thereby achieving thermal decoupling of the pump housing from the motor housing, since heat cannot be transferred via a direct axial connection between the housings.

[0011] Advantageously, such a heat conduction barrier is designed as a recess in the material, the space of which is usually filled with air, which is known to be a particularly good insulator, and therefore constitutes a barrier to heat conduction. In an alternative variant of the invention, such a heat conduction barrier may also be in the form of a material with a particularly low thermal conductivity, for example a material based on a ceramic material.

[0012] According to the invention, the coupling unit directly connects the pump housing and the motor housing. In principle, no other components are required to provide this connection. In order to reduce manufacturing costs, a reduction in the number of components is advantageous in most cases.

[0013] The coupling unit is preferably constructed in the shape of a cylinder and / or a trumpet funnel. This spatial configuration is particularly advantageous for achieving additional cooling of the coupling unit by the cooling airflow provided by the motor fan. In alternative variants of the invention, the coupling unit can also be constructed in the shape of a cone and / or a parallelepiped.

[0014] In a variant of the invention, the coupling unit is constructed integrally with the motor-side pressure cover of the pump housing and / or with the pump-side motor cover, which advantageously results in a particularly compact design of the coupling unit and a pump design with dimensions that can also be used in installations with limited space.

[0015] According to the invention, the thermal conductivity of the joining unit 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 greater than 10 W / m·K, preferably greater than 20 W / m·K, in particular greater than 30 W / m·K. The joining unit is preferably manufactured from grey cast iron or aluminium using a casting method.

[0016] Ideally, the thermal conductivity of the thermally conductive barrier is less than 20 W / m·K, preferably less than 15 W / m·K, especially less than 10 W / m·K, and / or greater than 0.002 W / m·K, preferably greater than 0.05 W / m·K, especially greater than 0.1 W / m·K.

[0017] According to the invention, the width of the recess in the material 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. Advantageously, the material thickness of the coupling unit 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. The coupling unit according to the invention is of a slim construction type, using materials that are easy to handle, and at the same time is characterized by a stable and vibration-resistant construction.

[0018] According to the invention, the coupling unit is constructed on the pump side and / or on the motor side as a bearing carrier, which results in a particularly compact construction of the coupling unit and at the same time reduces the number of components and the complexity of assembly.

[0019] The coupling unit according to the invention is characterized by a compact axial construction type in which the entire heat conduction path is extended by the insertion of a recess in the material.

[0020] Other features and advantages of the present invention will be apparent from the description of the embodiments given with reference to the drawings, and from the drawings themselves. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 2 is a cross-sectional view of a centrifugal pump unit. [Figure 2] FIG. [Figure 3] FIG. 10 is a perspective view of another coupling unit structure. [Figure 4] FIG. 10 is a perspective view of a third coupling unit structure. [Figure 5] FIG. 10 is a perspective view of another coupling unit structure. DETAILED DESCRIPTION OF THE INVENTION

[0022] 1 shows a pump structure with a coupling unit 1 connecting a pump housing 3 and an electric motor housing 7. The centrifugal pump shown in this embodiment is used to transport fluids that may have high temperatures under some circumstances.

[0023] Fluid enters the pump housing 3 of the centrifugal pump through a suction nozzle 2. An impeller 4 is arranged inside the pump housing 3. The impeller 4 transfers kinetic energy to the fluid, which leaves the centrifugal pump through a pressure nozzle (not shown in FIG. 1). The space containing the fluid and impeller 4 is delimited by the pump housing 3 and the housing cover 5. The impeller 4 is connected in a rotationally fixed manner to a shaft 9, which drives the impeller 4 via a motor structure 13. The motor structure 13 includes a rotor 10, a stator 8, the shaft 9, a pump-side motor cover 6, and the motor housing 7. A bearing carrier carrying bearings 11 is arranged in the motor cover 6.

[0024] 1 , it can be clearly seen that a thermally conductive barrier 12 is provided over the entire axially central portion between the pump housing 3 and the motor housing 7. Such a thermally conductive barrier 12 is configured such that there is no direct axial connection between the housing components, thereby providing a stronger thermal decoupling of the housings 3 and 7. In this advantageous manner, the thermal conduction paths extend exclusively radially, without increasing the axial structural length of the coupling unit 1.

[0025] FIG. 2 shows a perspective view of the coupling unit 1. A connecting plate 15 for connecting to the motor cover 6 (not shown) is connected to a connecting plate 16 by connecting webs 14 for connecting to the housing cover 5 (not shown) of the pump housing 3. The coupling unit 1 has a plurality of heat-conducting barriers 12, which in this embodiment are designed as recessed material. In an alternative variant, the heat-conducting barriers may be in the form of a material with poor thermal conductivity. The connecting webs 14 prevent engagement with the rotating shaft 9. The structural design of the connecting webs 14 results in the coupling unit 1 providing a very long circumferential heat conduction path with the shortest possible axial structural space. The cooling airflow provided by the motor fan (not shown) and flowing through the cooling ribs of the motor housing 7 toward the coupling unit 1 can dissipate the heat transferred by the connecting webs 14 from the pump housing 3 in addition to the heat-conducting barriers 12, so that only a very small heat input reaches the motor cover 6. As a result of the particularly advantageous construction of the coupling unit 1, the pump housing 3 and the electric motor structure 13 are thermally decoupled to a greater extent.

[0026] FIG. 3 shows a perspective view of another embodiment of the coupling unit 1. A connecting plate 15 for connection to the motor cover 6 (not shown in this example) is connected by connecting webs 14 to a connecting plate 16 for connection to the housing cover 5 (also not shown) of the pump housing 3. The coupling unit 1 has a plurality of heat-conducting barriers 12, which in this embodiment are in the form of material recesses. In this variant of the invention, the connecting webs 14 are in the form of cylindrical elements, each integrally constructed with the connecting plates 15 and 16 via four small connecting elements. Material recesses are located between the small connecting elements, between the cylindrical elements and the connecting plate 16, and between the cylindrical elements and the connecting plate 15, respectively. This variant of the coupling unit 1 advantageously thermally decouples the motor structure 13 from the pump housing 3 and, at the same time, configures the coupling unit 1 in a particularly stable and vibration-resistant manner.

[0027] Figure 4 shows a perspective view of a third variant of the coupling unit 1 according to the invention. A connecting plate 15 for connection to a motor cover 6 (not shown here) is connected by a connecting web 14 to a connecting plate 16 for connection to a housing cover 5 (also not shown) of the pump housing 3. The coupling unit 1 has a number of heat-conducting barriers 12, which in this embodiment are in the form of material recesses. The coupling unit 1 of Figure 4 corresponds to the coupling unit 1 of Figure 3. In this example, the cylindrical component is further provided with additional axially arranged heat-conducting barriers 12 in the form of material recesses. This therefore extends the radial and / or axial distance of heat conduction from the pump housing 3 towards the motor structure 13 without increasing the axial length of the coupling unit 1.

[0028] In this example, the thermal conductivity of the bonding unit 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 greater than 10 W / m·K, preferably greater than 20 W / m·K, in particular greater than 30 W / m·K. The thermal conductivity of the thermally conductive barrier 12 in this example is less than 20 W / m·K, preferably less than 15 W / m·K, in particular less than 10 W / m·K, and / or greater than 0.002 W / m·K, preferably greater than 0.05 W / m·K, in particular greater than 0.1 W / m·K.

[0029] The width of the thermally conductive barrier 12, which in this embodiment is in the form of a recess in the material, 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. The material thickness of the connection unit 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.

[0030] 5 shows a perspective view of the coupling unit 1. A connecting plate 15 for connection to the motor cover 6, not shown here, is connected by connecting webs 14 to a connecting plate 16 for connection to the housing cover 5 (also not shown) of the pump housing 3 via a hollow cylindrical sleeve 17 and an additional connecting web 14.

[0031] The connection unit 1 has a number of heat-conducting barriers 12, which in this embodiment are in the form of recesses in the material. In an alternative variant, the heat-conducting barriers may also be made of a material with low thermal conductivity. The connecting web 14 and the hollow cylindrical sleeve 17 prevent engagement at the rotating shaft 9 and also guide the forces acting via the mass of the motor structure 13 from the motor housing 7 to the base of the pump. To this end, the hollow cylindrical sleeve 17 is additionally reinforced around two recesses 18 in the embodiment shown.

[0032] The thermal conduction barrier 12 located near the connecting web 14 limits the heat conduction to a minimum and, in particular, by extending the connecting web 14 radially inward, extends the heat conduction path in the direction from connecting plate 16 to connecting plate 15.

[0033] The parallelepiped connecting plate 16 is constructed with rounded edges, and the connecting webs 14 each start from the center and extend radially inwards like a pillar. The hollow cylindrical sleeve 17 has additional heat-conducting barriers 12 in the form of recesses in the material, which extend the heat-conducting path and thus effectively thermally decouple the pump housing 3 and the motor housing 7.

[0034] The cooling airflow provided by the motor fan (not shown) and flowing through the cooling ribs of the motor housing 7 in the direction towards the coupling unit 1 can, in addition to the heat conduction barrier 12, dissipate the heat transmitted by the connecting webs 14 from the pump housing 3, so that only a very small heat input reaches the motor cover 6.

Claims

1. A pump structure having a coupling unit (1) connecting a pump housing (3) and an electric motor housing (7) to each other, At least one thermally conductive barrier (12) is arranged inside the coupling unit (1), the coupling unit (1) comprises a first connecting plate (15) for connection to the motor housing (7), a second connecting plate (16) axially spaced from the first connecting plate (15) for connection to the pump housing (3), and a plurality of connecting webs (14) connecting the first connecting plate (15) and the second connecting plate (16); 1. A pump structure, characterized in that the at least one heat conduction barrier (12) is designed as a recess in the material of the connecting unit (1) and is arranged in the area surrounded by the connecting webs over the entire axial range between the first connecting plate (15) and the second connecting plate (16).

2. 2. A pump arrangement according to claim 1, characterized in that the coupling unit (1) directly connects the pump housing (3) and the electric motor housing (7).

3. 3. A pump arrangement according to claim 1 or 2, characterized in that the coupling unit (1) is constructed cylindrically and / or trumpet-funnel-shaped and / or conically and / or the coupling unit (1) is designed as a body with a polygonal base surface.

4. 4. A pump arrangement according to any one of claims 1 to 3, characterized in that the coupling unit (1) is constructed integrally with the motor-side pressure cover (5) of the pump housing (3).

5. 5. A pump arrangement according to any one of claims 1 to 4, characterized in that the coupling unit (1) is constructed integrally with a pump-side motor cover (6).

6. 6. A pump arrangement according to any one of claims 1 to 5, characterized in that the thermal conductivity of the bonding unit material is less than 400 W / m·K and / or greater than 10 W / m·K.

7. 7. A pump arrangement according to any one of claims 1 to 6, characterized in that the thermal conductivity of the thermally conductive barrier (12) is less than 20 W / m·K and / or greater than 0.002 W / m·K.

8. 8. A pump arrangement according to any one of claims 1 to 7, characterized in that the width of the recess in the material is greater than 0.5 mm and / or less than 30 mm.

9. A pump arrangement according to any one of claims 1 to 8, characterized in that the material thickness of the connecting unit (1) is greater than 1 mm and / or less than 14 mm.

10. 10. Pump arrangement according to any one of claims 1 to 9, characterized in that the coupling unit (1) is constructed on the pump side as a pressure cover and / or on the electric motor side as a bearing carrier.

11. The connecting web (14) has a first portion extending in the circumferential direction, a first connecting element extending in the axial direction and connected to the first connecting plate (15), and a second connecting element extending in the axial direction and connected to the second connecting plate (16), the first connecting element and the second connecting element being arranged at different positions from each other in the circumferential direction; 11. A pump arrangement according to any one of claims 1 to 10, characterized in that a path of heat conduction from the second connecting plate (16) to the first connecting plate (15) extends along the second connecting element, the first part and the first connecting element.

Images