Spacer for a rotating member attached to a drive shaft

Abstract

The present invention relates to a spacer (1) for a rotating member (e.g., an impeller of a centrifugal pump) that is attached to a drive shaft (50). The spacer (1) of the present invention has a substantially tubular body (2) that forms a seat (3) for receiving the drive shaft (50). The substantially tubular body (2) is formed by bending a plate-like body made of a rigid material around a main axis (30) of an extension of the seat (3). The spacer of the present invention has a simple structure and is easy to manufacture.

Description

[Technical field]

[0001] The present invention relates to a spacer for a rotating member attached to a drive shaft. More particularly, the present invention relates to a spacer for an impeller that is attached to the drive shaft of a centrifugal pump. [Background technology]

[0002] As is known, a centrifugal pump is a hydrodynamic machine used in many technical fields to increase the pressure of a liquid. A centrifugal pump typically includes one or more pump stages, each having an impeller attached to a drive shaft and rotating within a pump case.

[0003] In a multi-stage centrifugal pump, each stage is arranged in series to progressively increase the pressure of a liquid that is mechanically transported from the intake to the outlet of the pump. With this configuration, the impellers are supported by the drive shaft and spaced apart from one another by adapted spacers.

[0004] The known spacer essentially consists of a body of generally tubular shape defining two opposing abutment surfaces, one of which has a trumpet-like flared shape. Commercially available spacers are not entirely satisfactory.

[0005] First, it should be considered that the plastic deformation required to form the flared abutment surfaces may compromise the structural integrity of the spacer. Another drawback is that the two abutment surfaces are not perfectly parallel to each other, which adversely affects the functionality of the rotating member.

[0006] From a manufacturing standpoint, such spacers are relatively laborious to manufacture and, as a result, are quite expensive.

[0007] Patent Document 1 (CN212803607U) discloses a submerged multi-stage centrifugal pump having a plurality of lower clamp blocks arranged side by side in the circumferential direction and integrally arranged at the lower end of the interstage sleeve. The impeller has a groove assembly for embedding in the upper clamp block or the lower clamp block.

[0008] Patent document 2 (US8678758B2) discloses an electric submersible pump having a housing having a head and a base, a shaft arranged to rotate within the housing, an impeller stack including a ceramic impeller mounted along the shaft, a diffuser stack including a diffuser disposed within the housing, and a spring sleeve including axially spaced, overlapping tangential slots mounted along the shaft for applying a compressive force between the shaft and the impeller stack. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] China CN212803607U [Patent Document 2] US Patent No. 8678758 (B2) Summary of the Invention [Problem to be solved by the invention]

[0010] It is an object of the present invention to provide a spacer for a rotating member mounted on a drive shaft which overcomes the drawbacks of the cited prior art. Within the scope of the above objectives, a particular object of the present invention is to provide a spacer that is safer and mechanically stronger.

[0011] It is a further object of the present invention to provide a spacer having abutment surfaces which are perfectly parallel to one another. It is a further object of the present invention to provide a spacer which is structurally simple yet highly effective and efficient to use. [Means for solving the problem]

[0012] This and these objects, as well as others which will become more apparent hereinafter, are achieved by a spacer for a rotating member mounted on a drive shaft, as claimed in the accompanying claims.

[0013] Further features and advantages will become more apparent from the description of preferred, but not exclusive, embodiments of the spacer according to the invention, illustrated by way of non-limiting example in the accompanying drawings, in which: [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view of a spacer according to the present invention. [Diagram 2] FIG. 2 is a front view of a spacer according to the present invention. [Diagram 3] FIG. 2 is a side view of a spacer according to the present invention. [Figure 4] FIG. 2 is a plan view of a spacer according to the present invention. [Diagram 5] FIG. 2 is a partial cross-sectional perspective view of a pump fitted with a spacer according to the present invention; [Figure 6] FIG. 2 is another partial cross-sectional perspective view of a pump fitted with a spacer according to the present invention. [Figure 7] FIG. 13 is a perspective view of a spacer according to a further aspect of the present invention. [Figure 8] FIG. 8 is a front view of the spacer of FIG. [Figure 9] FIG. 9 is a plan view of the spacer of FIGS. 7 and 8. [Figure 10] FIG. 13 is a perspective view of a spacer according to a further aspect of the present invention. [Figure 11] FIG. 11 is a front view of the spacer of FIG. [Figure 12] FIG. 12 is a plan view of the spacer of FIGS. 10 and 11. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [Embodiment of Figs. 1 to 6] 1 to 6, a spacer according to the present invention is indicated generally by the reference numeral 1. The spacer 1 is adapted to be mounted on a drive shaft 50 of a multi-stage centrifugal pump 60, where it is interposed between two adjacent impellers 61. Multi-stage centrifugal pumps are known per se and will not be described in detail here.

[0016] According to the invention, the spacer 1 has a substantially tubular body 2 forming a seat 3 for the drive shaft, i.e. shaft 50. The tubular body 2 is formed by bending a plate-like body of rigid material about the main axis 30 of the seat 3. Preferably, the plate-like body forming the main body 2 has a substantially rectangular shape and is made of a metallic material, preferably stainless steel.

[0017] In this embodiment, the cross-sectional shape of the main body 2 is substantially circular. Alternatively, the body 2 may have an elliptical, polygonal and / or mixed linear cross section.

[0018] The body 2 extends between two axial ends 4 , 5 which are parallel to one another and define respective axial abutment surfaces perpendicular to the main axis 30 . Advantageously, the spacer 1 comprises at least a first turn-up portion 6 extending substantially between the two axial ends 4 , 5 of the body 2 , and preferably also a second turn-up portion 7 .

[0019] The first and second folded portions 6, 7 are formed integrally with the main body 2 and are formed by bending the plate-shaped main body around a first bending axis 31 and a second bending axis 32, which are parallel to each other and substantially parallel to the main axis 30.

[0020] The spacer 1 is preferably constructed of a single part having a cross-section with a substantially open contour, formed by bending an original plate-like body around a main axis 30, a first bending axis 31 and a second bending axis 32, as shown in FIG. 4, so as to integrally provide the body 2 and the first and second folded portions 6, 7.

[0021] In practice, the first and second folded portions 6, 7 are formed by bending two opposing edges of the original plate-like body from which the body 2 is formed and therefore have an elongated and / or strip-like or band-like shape, preferably converging radially towards the main axis 30.

[0022] The first and second folded portions 6 , 7 are located at opposite edges of a slit 8 extending parallel to the main axis 30 between the two ends 4 , 5 of the body 2 . In accordance with further aspects of the invention, the fold back portion may be located at any other point on the cross-sectional profile of the spacer.

[0023] The first and second folded portions 6, 7 are plastically deformed during bending, which work-hardens the first and second folded portions 6, 7, thereby improving the hardness and mechanical strength of the spacer 1. Preferably, the bending is cold bending, however hot bending with subsequent material hardening and tempering treatments can also be used.

[0024] [Embodiment of Figs. 7 to 9] According to a further aspect of the invention shown in Figures 7 to 9, a spacer, designated by reference numeral 101, has at least one (and preferably both) axial abutment surfaces formed by the two axial ends 4, 5 of the body 2 and having a moulded configuration.

[0025] Advantageously, this molded arrangement acts as an anti-rotational connection between the spacer 101 and the rotating members between which it resides, in this example the rotating members being constituted by two impellers. In this embodiment, the molded formations are formed by a plurality of alternating raised portions 109a and recessed portions 109b.

[0026] [Embodiment of Figs. 10 to 12] According to a further aspect of the invention shown in Figures 10 to 12, the spacer (herein designated by reference numeral 201) has a plurality of mutually fused (integral) folded portions 206 extending substantially between the two axial ends 4, 5 of the body 2.

[0027] The folded-back portions 206 are formed integrally with the main body 2 and are formed by bending the plate-shaped main body about respective bending axes 231 which are parallel to each other and substantially parallel to the main axis 30 . Each folded portion 206 blends with an adjacent folded portion 206 such that the cross section of the body 2 has a wavy profile, forming an alternating pattern of raised portions (protrusions) and recessed portions.

[0028] In the embodiment shown in Figures 7 to 12, elements which correspond to elements already described with reference to the embodiment shown in Figures 1 to 6 are indicated with the same reference numerals.

[0029] In fact, it has been found that the present invention accomplishes its intended objectives and provides a significantly improved spacer over prior art spacers. In fact, from the above, it is clear that the spacer according to the invention is structurally simple and easy to manufacture, while at the same time having better stiffness and strength properties than prior art spacers.

[0030] The spacers according to the invention are particularly versatile in terms of processing economy, since it is possible to produce spacers of different ratios using a single tooling by simply adjusting the initial cutting dimensions of the plate-shaped body. The significant simplification in manufacturing also results in a significant reduction in manufacturing costs.

[0031] A further advantage of the spacer according to the invention is that its two abutment surfaces are perfectly parallel to one another, improving the functionality of the rotating members with which they are mated.

[0032] This application claims priority to Italian Patent Application No. 102022000005111, filed March 16, 2022, the subject matter of which is incorporated herein by reference. [Explanation of symbols]

[0033] 1 Spacer 2. Substantially tubular body 3 Seat 4,5 Two axial ends 6 First fold 7 Second fold 8 Slit (gap) 30 Main axis of seat 31 First bending axis 32 Second bending axis 50 Drive shaft 101 Spacer 201 Spacer 206 Multiple mutually fused (integrated) folded parts 213 Each bending axis

Claims

1. A spacer for a rotating member attached to a drive shaft, comprising:

1. A spacer comprising a substantially tubular body forming a seat for receiving a drive shaft, the substantially tubular body being formed by bending a plate-like body made of a rigid material about a major axis of an extension of the seat.

2. 2. The spacer according to claim 1, comprising at least a first folded portion extending substantially between two axial ends of the substantially tubular body, the first folded portion being integrally formed with the substantially tubular body and formed by bending the plate-like body about a first bending axis substantially parallel to the main axis.

3. 3. A spacer as claimed in claim 1 and / or 2, characterized in that it comprises a second folded portion extending substantially between the two axial ends of the substantially tubular body, the second folded portion being integrally formed with the substantially tubular body and formed by bending the plate-like body about a second bending axis substantially parallel to the first bending axis and the main axis.

4. A spacer according to one or more of claims 1 to 3, characterized in that the first folded portion and the second folded portion face each other on opposite sides of a gap extending substantially between the two axial ends of the substantially tubular body.

5. A spacer according to one or more of the preceding claims, characterized in that the first and second folded portions substantially converge towards the main axis.

6. A spacer according to one or more of claims 1 to 5, characterized in that it comprises a plurality of folded portions which are integral with each other and extend substantially between the two axial ends of the substantially tubular body, the folded portions being formed integrally with the substantially tubular body and which are formed by bending the plate-like body about respective bending axes which are parallel to each other and substantially parallel to the main axis.

7. A spacer as claimed in one or more of claims 1 to 6, wherein each of the plurality of folded portions merges with an adjacent folded portion to provide a cross-section in the substantially tubular body, the cross-section having a wavy profile with alternating protrusions and recesses.

8. A spacer according to one or more of the preceding claims, comprising one or more regions of strain hardening material extending substantially through each turn-up portion.

9. A spacer according to one or more of the preceding claims, characterized in that the two axial ends of the substantially tubular body form respective axial abutment surfaces which are parallel to one another.

10. A spacer according to one or more of the preceding claims, characterized in that at least one of the axial abutment surfaces has a shape adapted to form an anti-rotation constraint between the spacer and the rotating member between which it is interposed.

11. Spacer according to one or more of the preceding claims, characterized in that the substantially tubular body has a cross-section with a substantially open profile.

12. A spacer according to one or more of the preceding claims, characterized in that the plate-like body has a substantially rectangular shape.

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