EP3889437A1

EP3889437A1 - Impeller assembly for a centrifugal pump

Info

Publication number: EP3889437A1
Application number: EP20167250.8A
Authority: EP
Inventors: Silvano Pedrollo
Original assignee: Pedrollo SpA
Current assignee: Pedrollo SpA
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2021-10-06

Abstract

The impeller assembly associable with a centrifugal pump comprises a first disk (10) and a second disk (20) firmly assembled with each other. The first disk (10) is provided with a central hole (11) and a plurality of ribs (13) obtained by pressing on a face of the same first disk facing the second disk (20). The second disk (20) is provided with a central hole (21) and a rim (22) protruding from said central hole (21). Said ribs (13) are configured such that they shape a plurality of channels (14) separated by the same ribs between the first disk (10) and the second disk (20).

Description

Technical field

The present invention relates to an impeller assembly associable with a centrifugal pump.

Prior art

The employment of centrifugal pumps for domestic, agricultural or industrial use is currently known, in particular for pumping water. These pumps comprise one or more impeller assemblies capable of being rotated by a suitable motor member, generally of the electric type.
More specifically, centrifugal pumps use the centrifugal effect of the impeller assembly to move the liquid. For this purpose, the impeller sucks the liquid from an axial suction inlet and transfers mechanical energy to it, transmitted by the motor. The impeller is provided with a series of curved blades, which form channels with a growing section, from the center to the periphery. The liquid entering the central part of the impeller passes through these channels, converting the kinetic energy transmitted by the movement of the impeller into pressure energy.
According to a known embodiment, the impeller assembly consists of two suitably shaped discoidal elements, arranged coaxial to the rotation axis and connected by a series of blades radially arranged inside the interspace defined between said discoidal elements. The discoidal elements are centrally provided with means of fixing to a transmission shaft, rotatable around the axis of rotation.
The patent application WO 2016/060221 shows an impeller assembly of the above-mentioned type.
It has been found that this solution, even though it is very common, has some room for improvement. In particular, a reduction in the cost of production of the impeller assembly is still required, such that it significantly affects the overall cost of the centrifugal pump.

Disclosure

The present invention aims at solving the mentioned problems, by devising an impeller assembly associable with a centrifugal pump, which enables a high efficiency to be achieved even with a structure having relatively cheap cost.
Within this aim, it is an object of the present invention to provide an impeller assembly that may be made by means of a reduced group of components.
Still another object of the invention is to provide an impeller assembly of simple construction and functional conception, provided with reliable operation and versatile use.
The above-mentioned objects are achieved, according to the present invention, by the impeller assembly associable with a centrifugal pump as in claim 1.
According to the invention, the impeller assembly comprises a first disk and a second disk made of cold pressed steel.
Preferably, said first disk and said second disk have the same external diameter.
Said first disk and said second disk are firmly assembled with each other, preferably by welding.
Said first disk has a central hole and a plurality of ribs obtained by pressing on a face of the same first disk facing said second disk.
Said second disk is provided with a central hole.
Preferably said second disc is provided with a rim protruding from said central hole.
Said first disk and said second disk are firmly assembled with each other so as to form, between the said first disk and the said second disk, a plurality of channels separated by said ribs.
Preferably, said first disk and said second disk are assembled by welding.
Preferably, a cavity is defined between said first disk and said second disk, whose height is given by the height of said ribs.
Preferably, said ribs have an inverted U-shaped configuration in section, having constant dimensions along the entire development of the rib.
Preferably, said ribs extend from the center towards the periphery of said first disk according to a curvilinear profile, so that said channels take a divergent shape.
According to an embodiment, said first disc has a circular lowering at said central hole, suitable for defining the coupling seat with a member of junction to a shaft for transmitting the motion to the impeller assembly.
According to an embodiment, said central hole of the first disk is shaped according to a prismatic profile to couple with a corresponding grooved portion of a shaft for transmitting the motion to the impeller assembly.
The present invention also relates to a centrifugal pump comprising at least one impeller assembly capable of being operated in rotation by a shaft of transmission of motion, axially assembled with the same impeller assembly, and comprising a first disk and a second disk made of cold pressed steel, said first disc being provided with a plurality of ribs obtained by pressing on a face of the same first disc facing said second disc, said first disc and said second disc being firmly assembled with each other so that a plurality of channels separated by said ribs is formed, between said first disk and said second disk.

Description of drawings

The details of the invention will become clearer from the detailed description of a preferred embodiment of the impeller assembly associable with a centrifugal pump according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, where:

Figure 1 shows an exploded perspective view of the impeller assembly according to the invention;
Figure 2 shows an axial section view of said impeller assembly;
Figure 3 shows an exploded perspective view of a second embodiment of the impeller assembly according to the invention;
Figure 4 shows an axial section view of the impeller assembly illustrated in Fig. 3.

Best mode

The impeller assembly 1 comprises a first disk 10 and a second disk 20 made of cold pressed steel and firmly assembled with each other, preferably by welding. The first disk 10 and the second disk 20 have substantially the same external diameter.
The first disk 10 has a central hole 11. The central hole 11 is made in the center of a circular lowering 12 of the surface of the first disk 10.
On the face of the first disk 10 facing the second disk 20 a plurality of ribs 13 is obtained by pressing, regularly distributed. The ribs 13 are configured such that they shape, between the first disk 10 and the second disk 20, a plurality of channels 14 separated by the ribs 13. In particular, the ribs 13 are capable of establishing the height of a cavity, which is thus made between the first disk 10 and the second disk 20, equal to the height of said channels 14.
The ribs 13 expand substantially from the center to the periphery of the first disk 10 along a curvilinear profile. The channels 14 defined by the ribs 13 therefore have a divergent shape.
In particular, the ribs 13 have an inverted U-shaped configuration in section having constant dimensions along the entire development of the rib.
The second disk 20 is provided with a central hole 21. A rim 22 having substantially the shape of a cylindrical sleeve protrudes from the edge of the central hole 21 of the second disk 20.
A member of junction 30 to the shaft for transmitting the motion to the impeller assembly 1, not shown in the drawings, is suitable to be associated with the central hole 11 of the first disk 10. The member of junction 30 is made up of a sleeve 31 externally shaping an annular rim 32 by means of which it is capable of resting, in a configuration of assembly, inside the circular lowering 12 of the first disk 10 (see in particular Fig. 2). The sleeve 31 axially has a truncated cone-shaped cavity 33 for coupling with the shaft for transmitting the motion to the impeller assembly 1.
According to a different embodiment, illustrated in figures 3 and 4, the first disc 10 has axially a hole shaped according to a prismatic profile, for example cross-like or the like, for clarity still indicated with number 11. The hole 11 is suitable for coupling with a corresponding suitably grooved portion of the shaft for transmitting the motion to the impeller assembly 1.
In practice, this different embodiment does not require the presence of a specific member of junction for coupling the shaft for transmitting the motion to the impeller assembly 1.
The operation of the impeller assembly is easily understood from the above description.
Manufacturing of the impeller assembly by means of two cold pressed steel discs simplifies the production process of the impeller assembly, making it less expensive. In particular, in place of the curved blades on the disc, which in the prior art form the channels of liquid flow, it is possible to make the ribs by pressing in a single piece with the first disc, that perform the same function.
Basically, it is possible to provide an impeller assembly that may be made by means of a very small number of components.
The impeller assembly according to the invention therefore achieves the aim of improving the impeller assemblies commonly used in the prior art.
In particular, the aim of providing an impeller assembly associable with a centrifugal pump, which achieves high efficiency, despite having a relatively cheap cost structure, is achieved.
The impeller assembly, described by way of example, may be modified according to the different requirements.
In the practical implementation of the invention, the materials that are used, as well as the shape and dimensions, may change any according to the requirements.
Should the technical features mentioned in any claim be followed by reference signs, such reference signs were included strictly with the aim of enhancing the understanding of the claims and hence they shall not be deemed restrictive in any manner whatsoever on the scope of each element identified for exemplifying purposes by such reference signs.

Claims

An impeller assembly associable with a centrifugal pump comprising a first disc (10) provided with a central hole (11) and a plurality of ribs (13) obtained by pressing on a face of said first disc (10); a second disk (20) provided with a central hole (21); wherein said first disk (10) and said second disk (20) are firmly assembled with each other, so that a plurality of channels (14) separated by the said ribs (13) are formed between said first disk (10) and said second disk (20).
An impeller assembly as in claim 1, characterized in that said first disk (10) and said second disk (20) are made of cold pressed steel.
An impeller assembly as in claim 1 or 2, characterized in that said first disk (10) and said second disk (20) are assembled by pressing.
An impeller assembly as in any one of the preceding claims, characterized in that said first disk (10) and said second disk (20) have the same external diameter.
An impeller assembly as in any one of the preceding claims, characterized in that between said first disc (10) and said second disc (20) is defined a cavity whose height is given by the height of said ribs (13).
An impeller assembly as in claim 5, characterized in that said ribs (13) have an inverted U-shaped conformation in section having constant dimensions along the entire development of the rib itself.
An impeller assembly as in claim 5 or 6, characterized in that said ribs (13) extend from the center towards the periphery of said first disk (10) according to a curvilinear profile, so that said channels (14) take a divergent shape.
An impeller assembly as in any one of the preceding claims, characterized in that said second disc (20) is provided with a rim (22) protruding from said central hole (21).
An impeller assembly as in any one of the preceding claims, characterized in that said first disk (10) has a circular lowering (12) at said central hole (11), suitable for defining the coupling seat with a member of junction (30) to a shaft for transmitting the motion to the impeller assembly.
An impeller assembly as in any one of the preceding claims, characterized in that said central hole (11) of the first disk (10) is shaped according to a prismatic profile to couple with a corresponding grooved portion of a shaft for transmitting the motion to the impeller assembly.
A centrifugal pump comprising at least one impeller assembly (1) capable of being driven in rotation by a shaft for transmitting the motion, assembled axially with the same impeller assembly (1), characterized in that said impeller assembly (1) comprises a first disk (10) provided with a central hole (11) and a plurality of ribs (13) obtained by pressing on one face of said first disk (10); a second disk (20) provided with a central hole (21); wherein said first disk (10) and said second disk (20) are firmly assembled with each other so that a plurality of channels (14) separated by the said ribs (13) are formed between said first disk (10) and said second disk (20).