Centrifugal pump

Abstract

Centrifugal pump (1) including: - at least one impeller (4, 4') configured to rotate around an axis (Z) in order to accelerate in a radial direction a fluid (F) to be pumped, and - an axial diffuser (18) positioned downstream of said impeller (4, 4'), and configured to divert said flow of the pumped fluid (F) from a radial direction to a substantially axial direction along said axis (Z), and characterized in that said axial diffuser (18) comprises a diffuser body (22) configured to contain, at least partially, at least one further component of the pump.

Description

FIELD OF INVENTION

[0001] The present invention concerns a pump, and in particular a centrifugal pump.STATE OF THE ART

[0002] Centrifugal pumps are known, such as the one represented in figure 1, in which the fluid to be pumped is accelerated from the center of the pump towards the periphery, by means of one or more impellers, which impart a centrifugal force to the fluid itself. In the case of a multistage pump, once the fluid exits the impeller G n , in order to be further accelerated by the impellers G n+1 following the first, the fluid is conveyed from the periphery towards the center by means of radial diffusers D, which also have radial channels C. Both in the case of a single-stage pump, and in the case of a multi-stage, downstream of the first impeller (or of the last, in the case of a multi-stage), the fluid is conveyed by the diffuser into the central area. This could involve an increase in axial space (z direction) to re-convey the fluid towards the radial periphery, on the path that the water must follow to reach the outlet. In fact, the continuous diversion of the fluid from the center to the periphery, and vice versa, leads to losses in efficiency.

[0003] This means that, downstream of the last impeller G n (in fig. 1 represented by G 2 ), a cap T configured to prevent the flow of the pumped fluid in a direction other than that of the delivery M must be positioned

[0004] It is, however, necessary to bring the flow of the outlet M back to the center, where the pump P has a mechanical seal (S) as a system to seal the water part from the air part.

[0005] Furthermore, since the mechanical seal is made between a fixed part and a rotating part, the mutual movement of these two parts must necessarily be lubricated, in particular, it is generally lubricated by the water set in motion by the pump.PURPOSES OF THE INVENTION

[0006] The aim of the present invention is to propose a pump, which allows to overcome the drawbacks of the known solutions.

[0007] Another purpose of the invention is to propose a pump that is compact.

[0008] Another purpose of the invention is to propose a pump that does not require mechanical sealing systems.

[0009] Another purpose of the invention is to propose a pump that has a wet rotor.

[0010] Another purpose of the invention is to propose a pump that has a high number of functions.

[0011] Another purpose of the invention is to propose a pump that presents a fluid flow with lower pressure drops, and, therefore, a higher efficiency of the machine.

[0012] Another purpose of the invention is to propose a pump that operates at low temperatures.

[0013] Another purpose of the invention is to propose a pump that is an alternative and / or improvement compared to known solutions.

[0014] Another purpose of the invention is to propose a pump that can be manufactured easily and quickly, and at low costs.

[0015] All these objects, and others which will clearly appear from the description, are obtained by means of a pump having the features described in claim 1.

[0016] Other structural and functional features of the present innovation and the relative advantages compared to the known art will be even clearer and more evident from an examination of the following description, referring to an exemplary and preferred, but not limiting, embodiment of the pump, which is the object of the present invention.BRIEF DESCRIPTION OF THE FIGURES

[0017] The present invention will now be described, by way of example and without limitation, according to some of its preferred embodiments, and with the aid of the attached figures, in which: figure 1 shows a state-of-the-art multistage centrifugal pump, figure 2 shows a multistage centrifugal pump according to the invention, figure 3 shows a rear view of the impellers and diffusers of a multistage pump according to the invention, figure 4 shows them in front view. DETAILED DESCRIPTION OF THE INVENTION

[0018] Below, the Z axis refers to the axis around which the pump impellers rotate. Below, F indicates the fluid flows that are generated by the pump in the embodiment, in which it comprises both a radial diffuser and an axial diffuser.

[0019] As is clear from figures 2 - 4, the present invention relates to a pump 1, in particular, a centrifugal pump. In particular, figures 2 - 4 show a multistage pump. It is clear that the present invention also relates to a single-stage pump.

[0020] Conveniently, the pump 1 comprises a motor body 2 configured to contain, at least partially, the components of the motor itself.

[0021] Advantageously, the pump 1 can comprise at least one impeller 4, and, in the embodiment shown, it can comprise a plurality of impellers 4, 4' positioned in series along a Z-axis, thus defining a multistage pump. Advantageously, the impellers can be of the open, semi-open, or, more preferably closed, type. In an embodiment not shown, the pump 1 according to the invention can comprise a single impeller 4.

[0022] Conveniently, the impellers 4, 4' can be moved by suitable motor means 6, which can be mechanically connected to the impellers themselves by means of a shaft 8 or, in an embodiment not shown, by means of magnetic means.

[0023] In a traditional manner, each impeller 4, 4' can define at least a first channel 10, and preferably a plurality of first channels 10, configured to allow the acceleration of the fluid from the center of the impeller itself towards its periphery, under the impulse of the rotation of the impeller itself.

[0024] Conveniently, the pump 1 can comprise, between an impeller 4 and the subsequent 4', at least one radial diffuser 12. Conveniently, the diffuser 12 can define at least a second channel 14 configured to convey the flow of fluid from an impeller 4 to the subsequent impeller 4', and, in particular, from the periphery of an impeller towards the center of the subsequent impeller 4'. In particular, therefore, the second channels 14 are of the radial type - i.e., they are configured to impart a speed to the flow that has radial and angular components much greater than the axial component.

[0025] Suitably said at least one radial diffuser can be positioned downstream of a first impeller 4 and upstream of a second impeller 4'.

[0026] An axial diffuser 18 can be conveniently positioned downstream of the last impeller 4'. Advantageously, the axial diffuser is configured to generate a flow F, which has a component along the Z-axis, and an angular component substantially greater than the radial component.

[0027] In an embodiment not shown, in which the pump according to the invention is a single-stage pump, there can be only one impeller 4 and only one diffuser, the latter of the axial type.

[0028] Advantageously, said axial diffuser 18 can be configured to convey the flow of fluid F from the periphery of the impeller 4', arranged further downstream, and therefore placed upstream of the diffuser itself, in an axial direction, for example towards the center of the pump 1 through suitable third channels 20.

[0029] Conveniently, the axial diffuser 18 can comprise a substantially toroidal diffuser body 22. Advantageously, the diffuser body 22 can define an internal cavity 21 configured to contain, at least partially, one or more further components of the pump itself. In particular, the diffuser body 22 can be configured to contain, at least partially, the motor body 2 of the pump 1, and, in particular, the rotor and the stator, which make up the motor itself.

[0030] Advantageously, in one embodiment, in which it is essentially discussed about a dry rotor pump, the fluid intended to be pumped may not be present inside the internal cavity 21.

[0031] Alternatively, in an embodiment, in which the pump has a wet rotor, water may be present inside the internal cavity 21, but this water may be contained inside the motor, and, in particular, may not be free to circulate inside the internal cavity 21.

[0032] Advantageously, in an embodiment not shown, the internal cavity 21 can contain one or more impellers and / or one or more diffusers.

[0033] Furthermore, in an embodiment not shown, the internal cavity 21 can contain, at least partially, the electronic components that allow the operation of the pump 1.

[0034] Advantageously, said electronic components can comprise at least one control and processing unit (not shown), configured to receive inputs from a user, possibly through appropriate input means, and to control, on the basis of said inputs, the operation of the pump, and in particular the speed of the motor means 6.

[0035] In particular, said internal cavity 21 is configured to contain at least partially, and preferably completely, at least one of the following components: the driving means 6 of the pump 1, preferably comprising at least one rotor and at least one stator, the electronic components that control the operation of the pump itself, at least one impeller, at least one diffuser, preferably of axial type, means, traditional in themselves, for self-priming pump 1, other hydraulic components, such as a Venturi tube.

[0036] Advantageously, said third channels 20 can be defined on the external surface of the diffuser body 22 by shaped radial protrusions 23, which can preferably in turn be defined by a raised perimeter edge 24, which encloses an interior substantially at the level of the external surface of the diffuser body 22.

[0037] Conveniently, the axial diffuser 18 can envelop, at least partially, the motor 4 of the pump 1.

[0038] Advantageously, particularly, for example, in the embodiment, in which the pump has a wet rotor, the axial diffuser 18 can be made of polymeric material, or, more preferably, of composite material, in order to simplify the production of the diffuser itself. Conveniently, in order to maintain sufficient thermal conductivity, the diffuser body 22 can have substantially thin side walls 22', for example a few millimeters thick.

[0039] In an alternative embodiment, the diffuser body can be made of metal, for example stainless steel, in order to obtain greater thermal conduction.

[0040] Conveniently, the diffuser body 22 can present, on the external surface, a plurality of stiffening ribs 25, in order to improve its mechanical resistance. Conveniently, said ribs 25 can be substantially parallel to the Z-axis and, preferably, cannot be inserted inside the third channels 20.

[0041] Advantageously, said third channels 20 can present a substantially screw / spiral direction around the Z-axis. Conveniently, the third channels 20 are divergent channels, i.e., they present a section that increases along the flow direction F and / or along the Z direction. Advantageously, the third channels can be directed to divert the flow, which upstream of the axial diffuser 18 presents a radial direction - i.e. a velocity that has a substantially lower axial component than the radial and angular one - in a substantially axial direction - i.e. a speed that has a radial component substantially lower than the axial and angular ones.

[0042] Substantially, therefore, upstream of the axial diffuser 18, the velocity components of the flow are mainly contained in the r-θ plane, while downstream of the axial diffuser 18 the velocity component is mainly towards z.

[0043] Advantageously, the third channels 20 are configured to be directed directly towards the outlet of the pump 1.

[0044] Conveniently, therefore, the pump 1 may not include a cap T downstream of the last diffuser as would be necessary if the last diffuser was of the radial type.

[0045] Advantageously, the third channels 20 can be aligned with the first channels 10 of the impeller 4' just upstream of the axial diffuser 18, allowing continuity of the flow F between the impeller 4' and the axial diffuser 18.

[0046] Advantageously, the axial diffuser 18 can remain substantially blocked in rotation, and therefore be substantially decoupled from the impeller 4' immediately upstream.

[0047] Furthermore, advantageously the body of the axial diffuser 20 can define an exhaust along its circumference - i.e. the flow F of fluid can be directed along the side wall 22' of the diffuser body 20.

[0048] Furthermore, the pump 1 according to the invention may advantageously not have specific systems S for the mechanical seal.

[0049] As is clear from what has been said, the centrifugal pump according to the invention is particularly advantageous as it allows: reducing overall dimensions, due to the inclusion of at least one pump component inside the diffuser body, and the number of components compared to a traditional pump, efficiently cooling the pump drive motor itself.

Examples

Embodiment Construction

[0018]Below, the Z axis refers to the axis around which the pump impellers rotate. Below, F indicates the fluid flows that are generated by the pump in the embodiment, in which it comprises both a radial diffuser and an axial diffuser.

[0019]As is clear from figures 2 - 4, the present invention relates to a pump 1, in particular, a centrifugal pump. In particular, figures 2 - 4 show a multistage pump. It is clear that the present invention also relates to a single-stage pump.

[0020]Conveniently, the pump 1 comprises a motor body 2 configured to contain, at least partially, the components of the motor itself.

[0021]Advantageously, the pump 1 can comprise at least one impeller 4, and, in the embodiment shown, it can comprise a plurality of impellers 4, 4' positioned in series along a Z-axis, thus defining a multistage pump. Advantageously, the impellers can be of the open, semi-open, or, more preferably closed, type. In an embodiment not shown, the pump 1 according to the invention can ...

FIELD OF INVENTION

[0001] The present invention concerns a pump, and in particular a centrifugal pump.STATE OF THE ART

[0002] Centrifugal pumps are known, such as the one represented in figure 1, in which the fluid to be pumped is accelerated from the center of the pump towards the periphery, by means of one or more impellers, which impart a centrifugal force to the fluid itself. In the case of a multistage pump, once the fluid exits the impeller G n , in order to be further accelerated by the impellers G n+1 following the first, the fluid is conveyed from the periphery towards the center by means of radial diffusers D, which also have radial channels C. Both in the case of a single-stage pump, and in the case of a multi-stage, downstream of the first impeller (or of the last, in the case of a multi-stage), the fluid is conveyed by the diffuser into the central area. This could involve an increase in axial space (z direction) to re-convey the fluid towards the radial periphery, on the path that the water must follow to reach the outlet. In fact, the continuous diversion of the fluid from the center to the periphery, and vice versa, leads to losses in efficiency.

[0003] This means that, downstream of the last impeller G n (in fig. 1 represented by G 2 ), a cap T configured to prevent the flow of the pumped fluid in a direction other than that of the delivery M must be positioned

[0004] It is, however, necessary to bring the flow of the outlet M back to the center, where the pump P has a mechanical seal (S) as a system to seal the water part from the air part.

[0005] Furthermore, since the mechanical seal is made between a fixed part and a rotating part, the mutual movement of these two parts must necessarily be lubricated, in particular, it is generally lubricated by the water set in motion by the pump.PURPOSES OF THE INVENTION

[0006] The aim of the present invention is to propose a pump, which allows to overcome the drawbacks of the known solutions.

[0007] Another purpose of the invention is to propose a pump that is compact.

[0008] Another purpose of the invention is to propose a pump that does not require mechanical sealing systems.

[0009] Another purpose of the invention is to propose a pump that has a wet rotor.

[0010] Another purpose of the invention is to propose a pump that has a high number of functions.

[0011] Another purpose of the invention is to propose a pump that presents a fluid flow with lower pressure drops, and, therefore, a higher efficiency of the machine.

[0012] Another purpose of the invention is to propose a pump that operates at low temperatures.

[0013] Another purpose of the invention is to propose a pump that is an alternative and / or improvement compared to known solutions.

[0014] Another purpose of the invention is to propose a pump that can be manufactured easily and quickly, and at low costs.

[0015] All these objects, and others which will clearly appear from the description, are obtained by means of a pump having the features described in claim 1.

[0016] Other structural and functional features of the present innovation and the relative advantages compared to the known art will be even clearer and more evident from an examination of the following description, referring to an exemplary and preferred, but not limiting, embodiment of the pump, which is the object of the present invention.BRIEF DESCRIPTION OF THE FIGURES

[0017] The present invention will now be described, by way of example and without limitation, according to some of its preferred embodiments, and with the aid of the attached figures, in which: figure 1 shows a state-of-the-art multistage centrifugal pump, figure 2 shows a multistage centrifugal pump according to the invention, figure 3 shows a rear view of the impellers and diffusers of a multistage pump according to the invention, figure 4 shows them in front view. DETAILED DESCRIPTION OF THE INVENTION

[0018] Below, the Z axis refers to the axis around which the pump impellers rotate. Below, F indicates the fluid flows that are generated by the pump in the embodiment, in which it comprises both a radial diffuser and an axial diffuser.

[0019] As is clear from figures 2 - 4, the present invention relates to a pump 1, in particular, a centrifugal pump. In particular, figures 2 - 4 show a multistage pump. It is clear that the present invention also relates to a single-stage pump.

[0020] Conveniently, the pump 1 comprises a motor body 2 configured to contain, at least partially, the components of the motor itself.

[0021] Advantageously, the pump 1 can comprise at least one impeller 4, and, in the embodiment shown, it can comprise a plurality of impellers 4, 4' positioned in series along a Z-axis, thus defining a multistage pump. Advantageously, the impellers can be of the open, semi-open, or, more preferably closed, type. In an embodiment not shown, the pump 1 according to the invention can comprise a single impeller 4.

[0022] Conveniently, the impellers 4, 4' can be moved by suitable motor means 6, which can be mechanically connected to the impellers themselves by means of a shaft 8 or, in an embodiment not shown, by means of magnetic means.

[0023] In a traditional manner, each impeller 4, 4' can define at least a first channel 10, and preferably a plurality of first channels 10, configured to allow the acceleration of the fluid from the center of the impeller itself towards its periphery, under the impulse of the rotation of the impeller itself.

[0024] Conveniently, the pump 1 can comprise, between an impeller 4 and the subsequent 4', at least one radial diffuser 12. Conveniently, the diffuser 12 can define at least a second channel 14 configured to convey the flow of fluid from an impeller 4 to the subsequent impeller 4', and, in particular, from the periphery of an impeller towards the center of the subsequent impeller 4'. In particular, therefore, the second channels 14 are of the radial type - i.e., they are configured to impart a speed to the flow that has radial and angular components much greater than the axial component.

[0025] Suitably said at least one radial diffuser can be positioned downstream of a first impeller 4 and upstream of a second impeller 4'.

[0026] An axial diffuser 18 can be conveniently positioned downstream of the last impeller 4'. Advantageously, the axial diffuser is configured to generate a flow F, which has a component along the Z-axis, and an angular component substantially greater than the radial component.

[0027] In an embodiment not shown, in which the pump according to the invention is a single-stage pump, there can be only one impeller 4 and only one diffuser, the latter of the axial type.

[0028] Advantageously, said axial diffuser 18 can be configured to convey the flow of fluid F from the periphery of the impeller 4', arranged further downstream, and therefore placed upstream of the diffuser itself, in an axial direction, for example towards the center of the pump 1 through suitable third channels 20.

[0029] Conveniently, the axial diffuser 18 can comprise a substantially toroidal diffuser body 22. Advantageously, the diffuser body 22 can define an internal cavity 21 configured to contain, at least partially, one or more further components of the pump itself. In particular, the diffuser body 22 can be configured to contain, at least partially, the motor body 2 of the pump 1, and, in particular, the rotor and the stator, which make up the motor itself.

[0030] Advantageously, in one embodiment, in which it is essentially discussed about a dry rotor pump, the fluid intended to be pumped may not be present inside the internal cavity 21.

[0031] Alternatively, in an embodiment, in which the pump has a wet rotor, water may be present inside the internal cavity 21, but this water may be contained inside the motor, and, in particular, may not be free to circulate inside the internal cavity 21.

[0032] Advantageously, in an embodiment not shown, the internal cavity 21 can contain one or more impellers and / or one or more diffusers.

[0033] Furthermore, in an embodiment not shown, the internal cavity 21 can contain, at least partially, the electronic components that allow the operation of the pump 1.

[0034] Advantageously, said electronic components can comprise at least one control and processing unit (not shown), configured to receive inputs from a user, possibly through appropriate input means, and to control, on the basis of said inputs, the operation of the pump, and in particular the speed of the motor means 6.

[0035] In particular, said internal cavity 21 is configured to contain at least partially, and preferably completely, at least one of the following components: the driving means 6 of the pump 1, preferably comprising at least one rotor and at least one stator, the electronic components that control the operation of the pump itself, at least one impeller, at least one diffuser, preferably of axial type, means, traditional in themselves, for self-priming pump 1, other hydraulic components, such as a Venturi tube.

[0036] Advantageously, said third channels 20 can be defined on the external surface of the diffuser body 22 by shaped radial protrusions 23, which can preferably in turn be defined by a raised perimeter edge 24, which encloses an interior substantially at the level of the external surface of the diffuser body 22.

[0037] Conveniently, the axial diffuser 18 can envelop, at least partially, the motor 4 of the pump 1.

[0038] Advantageously, particularly, for example, in the embodiment, in which the pump has a wet rotor, the axial diffuser 18 can be made of polymeric material, or, more preferably, of composite material, in order to simplify the production of the diffuser itself. Conveniently, in order to maintain sufficient thermal conductivity, the diffuser body 22 can have substantially thin side walls 22', for example a few millimeters thick.

[0039] In an alternative embodiment, the diffuser body can be made of metal, for example stainless steel, in order to obtain greater thermal conduction.

[0040] Conveniently, the diffuser body 22 can present, on the external surface, a plurality of stiffening ribs 25, in order to improve its mechanical resistance. Conveniently, said ribs 25 can be substantially parallel to the Z-axis and, preferably, cannot be inserted inside the third channels 20.

[0041] Advantageously, said third channels 20 can present a substantially screw / spiral direction around the Z-axis. Conveniently, the third channels 20 are divergent channels, i.e., they present a section that increases along the flow direction F and / or along the Z direction. Advantageously, the third channels can be directed to divert the flow, which upstream of the axial diffuser 18 presents a radial direction - i.e. a velocity that has a substantially lower axial component than the radial and angular one - in a substantially axial direction - i.e. a speed that has a radial component substantially lower than the axial and angular ones.

[0042] Substantially, therefore, upstream of the axial diffuser 18, the velocity components of the flow are mainly contained in the r-θ plane, while downstream of the axial diffuser 18 the velocity component is mainly towards z.

[0043] Advantageously, the third channels 20 are configured to be directed directly towards the outlet of the pump 1.

[0044] Conveniently, therefore, the pump 1 may not include a cap T downstream of the last diffuser as would be necessary if the last diffuser was of the radial type.

[0045] Advantageously, the third channels 20 can be aligned with the first channels 10 of the impeller 4' just upstream of the axial diffuser 18, allowing continuity of the flow F between the impeller 4' and the axial diffuser 18.

[0046] Advantageously, the axial diffuser 18 can remain substantially blocked in rotation, and therefore be substantially decoupled from the impeller 4' immediately upstream.

[0047] Furthermore, advantageously the body of the axial diffuser 20 can define an exhaust along its circumference - i.e. the flow F of fluid can be directed along the side wall 22' of the diffuser body 20.

[0048] Furthermore, the pump 1 according to the invention may advantageously not have specific systems S for the mechanical seal.

[0049] As is clear from what has been said, the centrifugal pump according to the invention is particularly advantageous as it allows: reducing overall dimensions, due to the inclusion of at least one pump component inside the diffuser body, and the number of components compared to a traditional pump, efficiently cooling the pump drive motor itself.

Examples

Embodiment Construction

[0018]Below, the Z axis refers to the axis around which the pump impellers rotate. Below, F indicates the fluid flows that are generated by the pump in the embodiment, in which it comprises both a radial diffuser and an axial diffuser.

[0019]As is clear from figures 2 - 4, the present invention relates to a pump 1, in particular, a centrifugal pump. In particular, figures 2 - 4 show a multistage pump. It is clear that the present invention also relates to a single-stage pump.

[0020]Conveniently, the pump 1 comprises a motor body 2 configured to contain, at least partially, the components of the motor itself.

[0021]Advantageously, the pump 1 can comprise at least one impeller 4, and, in the embodiment shown, it can comprise a plurality of impellers 4, 4' positioned in series along a Z-axis, thus defining a multistage pump. Advantageously, the impellers can be of the open, semi-open, or, more preferably closed, type. In an embodiment not shown, the pump 1 according to the invention can ...

Claims

1. Centrifugal pump (1) including: - at least one impeller (4, 4') configured to rotate around an axis (Z) in order to accelerate a fluid (F) to be pumped in a radial direction, and - an axial diffuser (18) positioned downstream of said impeller (4, 4'), and configured to divert said flow of the pumped fluid (F) from a radial direction to a substantially axial direction along said axis (Z), and characterized in that said axial diffuser (18) includes a diffuser body (22) configured to contain, at least partially, at least one further component of the pump.

2. Pump according to claim 1 characterized in that said at least one component of the pump contained in said axial diffuser includes at least one of the following: - the motor means (6) of said pump (1), - the electronic components that control the operation of the pump itself, - at least one impeller, - at least one diffuser, preferably of the radial type, or, otherwise, of the axial type - appropriate self-priming means, - other hydraulic components, for example at least a venturi tube.

3. Pump according to one or more of the previous claims characterized by the fact that said axial diffuser (18) is located downstream of the impeller (4') further downstream of the pump (1).

4. Pump according to one or more of the previous claims characterized by the fact that said axial diffuser (18) includes a diffuser body (22), on the external surface of which a plurality of channels (20) are defined by a raised perimeter edge (24), said channels (20) being configured to divert said flow F from radial to axial.

5. Pump according to one or more of the previous claims characterized by the fact that said channels (20) have an increasing section along the direction of advancement of the flow F.

6. Pump according to one or more of the previous claims characterized by the fact that said diffuser body is made of polymeric material, and preferably of composite material.

7. Pump according to one or more of the previous claims characterized in that the pump (1) is configured to keep the axial diffuser (18) substantially blocked in rotation.

8. Pump according to one or more of the previous claims characterized in that it comprises motor means (6) configured to operate said at least one impeller (4, 4') and that said motor means (6) are contained, at least partially, inside of said axial diffuser (18), and, in particular, inside said internal cavity (21).

9. Pump according to one or more of the previous claims characterized by the fact that the flow F is configured to flow along the side walls (22') of said diffuser body (22).

10. Pump according to one or more of the previous claims characterized by the fact that it does not have systems for mechanical sealing.

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