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The present invention relates to a circulation pump comprising a cartridge element and a shaft for driving an impeller of the pump, wherein the cartridge element at least partly encloses or surrounds the shaft.
BACKGROUND OF THE INVENTION
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There are many developments in the field of pumping, especially relating to pumping fluids like water and/or circulation pumps, and especially regarding the interworking of electrical engineering, mechanical engineering, and telecommunications, especially in view of more sustainability, ease of installation and/or reduction of maintenance efforts.
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Circulation pumps are well known and are nowadays used, for instance, in heating systems of industrial applications as well as private households for pumping a medium, especially water. Such circulation pumps comprise a shaft for driving an impeller, the shaft being supported and positioned by at least one bearing. Conventionally, such circulation pumps further comprise a cartridge or a cartridge element that at least partly encloses or surrounds the shaft. The bearing can be connected to the cartridge element by means of an outer ring of the bearing, thereby positioning the bearing and the shaft at a respective desired position.
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The entire circulation pump in general and the connection between the bearing and the cartridge element in particular is subject to temperature changes, for instance due to temperature changes of the pumped medium or due to changes of the external/ambient temperature. Temperature changes in turn can bring about difficulties, e.g. tightness issues between the bearing and the cartridge element. Lack of tightening can result in vibration. Vibration on the other hand can not only create or increase noise pollution but also result in mechanical damages. This problem is usually solved in the state of the art by different materials for the bearing and the cartridge element that respectively comprise a different thermal expansion ratio. For instance, the bearing can be manufactured by a ceramic material, while the cartridge element can be made of stainless steel. However, said use of different materials can still be suboptimal. Moreover, the usage of a steel cartridge element might create problems or at least reduce pump efficiency, as the cartridge element is arranged between a rotor and the stator of the pump which can be detrimental for magnetic field lines and therefore also for the transfer of energy from the stator to the rotor.
SUMMARY OF THE INVENTION
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An object of the present invention is to provide an optimized circulation pump that overcomes or reduces the negative effects of at least one of the abovementioned problems from the state of the art.
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The object of the present invention is achieved by a circulation pump comprising a cartridge element and a shaft for driving an impeller of the pump, wherein the cartridge element at least partly encloses or surrounds the shaft, wherein the shaft is supported and positioned, with regard to the cartridge element, by a bearing, and wherein the cartridge element comprises an internal surface comprising a support area for the bearing,
wherein an intermediate element is arranged as part of the cartridge element as a support for the bearing and in the support area. The intermediate element can be advantageously arranged between the cartridge element on the one hand and - especially an outer ring of - the bearing on the other hand. According to the inventive circulation pump, the use of an intermediate element can, with respect to the state of the art, further compensate for differences in the thermal expansion ratios of the materials employed. The intermediate element can further allow absorption of forces during assembly into the cartridge. Therefore, the use of an intermediate element can bring about an optimized tightness for a large temperature spectrum and, hence, eliminate or at least reduce vibrations, mechanical damages and noise level.
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According to a preferred embodiment of the invention, - in addition to the bearing - the shaft is supported and positioned, with regard to the cartridge element, by a further bearing, wherein the internal surface comprises a further support area for the further bearing, wherein a further intermediate element is arranged as part of the cartridge element as a support for the further bearing and in the further support area. Preferably, a ring-shaped brass element is arranged between the further bearing and the cartridge element. It is thereby advantageously possible to use one standard sized further bearing for a variety of different, especially different sized, pumps and thereby close a radial gap between the further bearing and the cartridge element by the brass element, which can reduce costs.
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According to an advantageous embodiment of the invention, the cartridge element is manufactured by overmoulding
- -- the intermediate element, or
- -- the intermediate element and the further intermediate element. It is thereby advantageously possible to use a steel, stainless steel, metallic, polymer, plastic or synthetic material for the intermediate element and/or the further intermediate element. Furthermore, by means of overmoulding the intermediate element and/or the further intermediate element, it is advantageously possible to realize a connection between the cartridge element on the one hand and the intermediate element and/or the further intermediate element on the other hand. It is also advantageously possible to easily position the intermediate element and/or the further intermediate element in or on the cartridge element. A polymer cartridge element has also the advantage of improving pump efficiency. Pump efficiency is due to a metallic part that can be detrimental for the magnetic field lines and the transfer of energy.
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According to a preferred embodiment of the invention, the intermediate element and/or the further intermediate element are metallic parts, especially stainless steel parts. Metallic parts, especially stainless parts, have the advantage of high mechanical stability. Especially a combination of a polymer cartridge element on the one hand and a metallic intermediate element and/or further intermediate element on the other hand is advantageous, as magnetic field lines will not be affected by a metallic cartridge element, while, at the same time, the one or two bearings can be properly mechanically supported by the metallic intermediate element and/or further intermediate element.
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According to an advantageous embodiment of the invention, the cartridge element is made - besides the intermediate element and/or the further intermediate element - of a plastic or a composite material, the composite material being especially a fiberglass-reinforced PPS - polyphenylene sulfide. A composite material has the advantage of providing sufficient mechanical stability as well as temperature resistance without significantly increasing wall thickness of the cartridge element. In other words, it is advantageously possible to maintain shape and strength of the cartridge element for a variety of operational conditions - especially due to temperature fluctuations, particularly of the pumped medium, for instance the heating medium - without significant effort increase. However, using a composite material made of plastic or fiberglass-reinforced polyphenylene sulfide, flow and arrangement of magnetic field lines in the circulation pump can be enhanced. Moreover, by changing the material of the cartridge element from metal, especially stainless steel, to a composite material, especially fiberglass-reinforced polyphenylene sulfide, increase of motor efficiency can be brought about. It is conceivable to reduce CO2 footprint by, for instance, 5% to 10%.
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According to a preferred embodiment of the present invention, the intermediate element is cap-shaped or cup-shaped or lid-shaped, the intermediate element comprising a ring-shaped portion extending in a circumferential direction and an end face portion, the end face portion preferably comprising three holes. The end face portion can comprise alternatively one or multiple grooves, scratches or any other design selection to prevent the intermediate element from rotating. A cup-shaped intermediate element has the advantage of providing a large contact area or surface that can be overmoulded. A large contact area or surface in turn can increase the stability of the connection between the cartridge element and the intermediate element. In other words, by means of a cup-shaped intermediate element, it is advantageously possible to avoid rotation between the intermediate element and the cartridge element. Therefore, a cup-shaped intermediate element can not only serve as an intermediate element between the cartridge element and the bearing for compensating thermal expansion differences but also as an anti-rotation means. For further strengthening the connection between the intermediate element and the cartridge element, the end face portion - that is the bottom of the cup - can comprise holes, for instance two, three or four holes that serve as recesses, wherein an overmoulding substance can enter the holes during the overmoulding process. Once the overmoulding substance has solidified in the recess/holes, a further (mechanical or form-fit) anti-rotation means can be provided, further strengthening the connection between the intermediate element and the cartridge element. For attaining the further strengthening, it is also - alternatively or additionally - conceivable that the end face portion of the cup-shaped intermediate element comprises two, three or four protrusions facing away from the ring-shaped portion of the intermediate element. The protrusions can be, for instance, formed as pins or be elongated protrusions. As a result, the overmoulded and solidified substance, that is the cartridge element, can comprise recesses that geometrically correspond to and directly surround the protrusions.
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Preferably, the further intermediate element is ring-shaped, the further intermediate element comprising a notch in a circumferential direction of the further intermediate element. The notch of the further intermediate element is an anti-rotation means. The notch particularly can have a variable depth along the circumferential direction, thereby avoiding rotation of the further intermediate element relative to the cartridge element. The cartridge element can comprise a protrusion that protrudes into the notch. Furthermore, the further intermediate element can be overmoulded, especially by the same overmoulding substance that the intermediate element is overmoulded. Alternatively or additionally to the notch, the further intermediate element can comprise one or many, for instance pin-shaped, protrusions that are arranged along the circumferential direction, wherein the cartridge element comprises recesses that geometrically correspond to the protrusions of the further intermediate element. The first support area and/or the further support area, wherein the intermediate element and/or the further intermediate element are arranged, can respectively comprise at least one lateral shoulder or lateral elevation or lateral protrusion in the internal surface of the cartridge element - that is a change in an internal diameter of the cartridge element - for respectively optimally positioning the intermediate element and/or the further intermediate element in the cartridge element.
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According to an advantageous embodiment of the invention, the cartridge element comprises a tube portion, wherein the tube portion comprises the internal surface with
- -- the first support area, or
- -- the first support area and the further support area. The cartridge element can be closed on a first side, especially on a side adjacent to the first support area and therefore facing away from the further support area. The cartridge element further can be open on a second side next to the further support area. The tube portion can be configured between the first side and the second side of the cartridge element. The impeller of the pump can be arranged advantageously on the second side or facing the second side.
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In an advantageous embodiment of the invention, the cartridge element comprises a flange, wherein the flange is separate from the tube portion and made of stainless steel, wherein a sealing element, especially an O-ring, is arranged between the flange and the cartridge element. A connecting portion of the flange can be arranged on the further intermediate element or on the further bearing.
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According to an alternative embodiment of the present invention, the cartridge element and the flange are configured as a one-piece element. The cartridge element and the flange can be a one-piece element. In other words, the cartridge element and the flange can be made of an overmoulding substance, both being manufactured preferably by fiberglass-reinforced polyphenylene sulfide.
BRIEF DESCRIPTION OF THE DRAWING
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- Figure 1a schematically and exemplarily illustrates in a cutaway and perspective view a first embodiment of an inventive circulation pump with a cartridge element, wherein an intermediate element and a further intermediate element are arranged as part of the cartridge element respectively in a support area and in a further support area.
- Figure 1b illustrates the cartridge element of the first embodiment of the inventive circulation pump shown in Figure 1a in the same cutaway and perspective view as figure 1a.
- Figure 1c illustrates the cartridge element of the first embodiment of the inventive circulation pump shown in the figures 1a and 1b in a perspective view.
- Figure 1d illustrates the intermediate element shown in the figures 1a and 1b in a perspective view.
- Figure 1e illustrates the further intermediate element shown in the figures 1a and 1b in a perspective view.
- Figure 2 schematically and exemplarily illustrates in a cutaway and side view a second embodiment of an inventive circulation pump with a cartridge element and a separate flange, wherein an intermediate element and a further intermediate element are arranged as part of the cartridge element respectively in a support area and in a further support area.
- Figure 3 schematically and exemplarily illustrates in a cutaway and side view a third embodiment of an inventive circulation pump with a cartridge element and a separate flange, wherein an intermediate element is arranged as part of the cartridge element in a support area.
- Figure 4 schematically and exemplarily illustrates in a cutaway and side view a fourth embodiment of an inventive circulation pump with a cartridge element and a separate flange, wherein an intermediate element is arranged as part of the cartridge element in a support area.
DETAILED DESCRIPTION
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The present invention will be described with respect to particular embodiments and with reference to certain drawings, but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are nonlimiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes.
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Where an indefinite or definite article is used when referring to a singular noun, e.g. "a", "an", "the", this includes a plural of that noun unless something else is specifically stated.
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Furthermore, the terms first, second, third and the like in the description and in the claims are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.
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Figure 1a schematically and exemplarily illustrates in a cutaway and perspective view a first embodiment of an inventive circulation pump 1 with a cartridge element 10, wherein an intermediate element 31 and a further intermediate element 32 are arranged as part of the cartridge element 10 respectively in a support area 21 and in a further support area 22. The circulation pump 1 comprises the cartridge element 10 and a shaft S for driving an impeller I of the pump 1. The cartridge element 10 at least partly encloses or surrounds the shaft S, wherein the shaft S is supported and positioned, with regard to the cartridge element 10, by a bearing 11. The cartridge element 10 further comprises an internal surface 20. The internal surface 20 comprises the support area 21 for the bearing 11 and the further support area 22 for a further bearing 12. The intermediate element 31 is arranged as part of the cartridge element 10 as a support for the bearing 11 and in the support area 21. Analogously, the further intermediate element 32 is arranged as part of the cartridge element 10 as a support for the further bearing 12 and in the further support area 22.
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The shaft S according to all embodiments illustrated in the figures is a hollow shaft. In the shaft S a filter 50 is arranged for filtering a pumped medium. The hollowness of the shaft S and the arrangement of the filter 50 inside the shaft S is due to the design of the circulation pump 1, according to which a pumped medium also enters an internal volume of the cartridge element 10. Such a circulation pump 1 can be called a wet runner due to its design allowing the medium to enter the cartridge element 10 by means of the hollow shaft S. The internal volume of the cartridge element 10 also serves as a rotoric chamber C. In other words, the circulation pump 1 comprises an electric motor with a stator 41 and a rotor 42, wherein the rotor 42 is arranged inside the rotoric chamber C. The rotor 42 is a permanent magnet.
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The intermediate element 31 and the further intermediate element 32 are stainless steel parts. Moreover, the cartridge element 10 is manufactured by overmoulding the intermediate element 31 and the further intermediate element 32. An overmoulding substance used for manufacturing the cartridge element 10 is fiberglass-reinforced polyphenylene sulfide. Furthermore, the cartridge element 10 comprises a flange F, the cartridge element 10 and the flange F being configured as a one-piece element. In other words, the flange F is also made of fiberglass-reinforced polyphenylene sulfide.
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The rotor 42 is connected to the shaft S by means of connecting means M. According to the embodiment shown in figure 1a, the rotor 42 is welded to the shaft S. However, other fixed connections between the rotor 42 and the shaft S are conceivable in other embodiments.
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Figure 1b illustrates the cartridge element 10 of the first embodiment of the inventive circulation pump 1 shown in Figure 1a in the same cutaway and perspective view as figure 1a. The cartridge element 10 comprises a tube portion T that comprises the internal surface 20 with the first support area 21 and the further support area 22.
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The intermediate element 31 is cap-shaped. It comprises a ring-shaped portion R extending in a circumferential direction and an end face portion E. The end face portion E comprises three holes H, only two of which are visible in figure 1b. When overmoulding the intermediate element 31, the overmoulding substance can enter the holes H. After solidification of the overmoulding substance, rotation of the intermediate element 31 relative to the tube portion T of the cartridge element 10 is avoided. The further intermediate element 32 is ring-shaped and comprises a notch in a circumferential direction of the further intermediate element 32. However, the notch is not visible in the figures.
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Figure 1 c illustrates the cartridge element 10 of the first embodiment of the inventive circulation pump 1 shown in the figures 1a and 1b in a perspective view. The cartridge element 10 is rotationally symmetric.
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Figure 1d illustrates the intermediate element 31 shown in the figures 1a and 1b in a perspective view.
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Figure 1e illustrates the further intermediate element 32 shown in the figures 1a and 1b in a perspective view.
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Figure 2 schematically and exemplarily illustrates in a cutaway and side view a second embodiment of an inventive circulation pump 1 with a cartridge element 10 and a separate flange F, wherein an intermediate element 31 and a further intermediate element 32 are arranged as part of the cartridge element 10 respectively in a support area 21 and in a further support area 22. Bearing 12 can be assembled or overmolded into further intermediate element 32. The flange F is separate from the tube portion T and made of stainless steel. An O-Ring 36 serving as a sealing element is arranged between the flange F and the tube portion of the cartridge element 10.
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Figure 3 schematically and exemplarily illustrates in a cutaway and side view a third embodiment of an inventive circulation pump 1 with a cartridge element 10 and a separate flange F, wherein an intermediate element 31 is arranged as part of the cartridge element 10 in a support area 21. The third embodiment differs from the second embodiment particularly by a missing further intermediate element 32 in the further support area 22. However, according to the third embodiment, a support element 38 is arranged between the flange F and the further bearing 12. The support element 38 is made of stainless steel and comprises a curved shape.
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Figure 4 schematically and exemplarily illustrates in a cutaway and side view a fourth embodiment of an inventive circulation pump 1 with a cartridge element 10 and a separate flange F, wherein an intermediate element 31 is arranged as part of the cartridge element 10 in a support area 21. The pump 1 according to the fourth embodiment does not comprise a further intermediate element 32. The flange F according to the fourth embodiment further comprises a U-shaped connecting portion U. The O-Ring 26 is arranged in or on the U-shaped connecting portion U and between the tube portion T of the cartridge element 10 and the further bearing 12.
Reference signs
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- 1
- Circulation pump
- 10
- Cartridge element
- 11
- Bearing
- 12
- Further bearing
- 20
- Internal surface
- 21
- Support area
- 22
- Further support area
- 31
- Intermediate element
- 32
- Further intermediate element
- 36
- O-Ring
- 38
- Support element
- 41
- Stator
- 42
- Rotor
- 50
- Filter
- B
- Brass element
- C
- Rotoric chamber
- E
- End face portion
- F
- Flange
- H
- Hole
- I
- Impeller
- M
- Connecting means
- R
- Ring-shaped portion
- S
- Shaft
- T
- Tube portion
- U
- Connecting portion