bridge element

Abstract

A stage piece for a multi-stage pump includes a first ring, a second ring, and a post. The post connects the first ring to the second ring and has a first radial end and a second radial end and a first side and a second side connecting the first and second ends. The first and second sides are arcuate and extend toward one another such that the first radial end is longer than the second radial end.

Description

Technical Field

[0001] This invention generally relates to a bridging stage for a multistage pump. In particular, this invention relates to a bridging stage for a multistage dual-volute pump, wherein the volute housings are axially separated. Background Technology

[0002] Conventional multistage pumps or multistage twin-volute pumps typically include an opposing impeller design. The opposing impellers are positioned in opposite directions to balance the axial thrust generated by the rotating elements. Some conventional multistage pumps include a bridging stage cast in, if the bridging geometry allows. This typically has at least four bridging posts connecting the two rings. Summary of the Invention

[0003] It has been found that in conventional multistage pumps, the stage components are located in the middle of the flow path, resulting in flow disturbance. Additionally, it has been found that conventional columns typically have thin cross-sections, making them difficult to cast without crack propagation. Furthermore, it has been found that if repeated attempts to cast a conventional design (which typically includes four columns) fail, the component will usually need to be formed via welding.

[0004] In view of the state of the prior art, a first aspect of this disclosure provides a stage component for a multi-stage pump, comprising a first ring, a second ring, and a post. The post connects the first ring to the second ring and has a first radial end and a second radial end, as well as a first side surface and a second side surface connecting the first and second ends. The first and second side surfaces are arcuate and extend toward each other, such that the first radial end is longer than the second radial end.

[0005] A second aspect of the invention provides a stage according to the first aspect, wherein the first radial end is arc-shaped.

[0006] A third aspect of the invention provides a stage according to the first or second aspect, wherein the second radial end extends radially inside the first and second rings.

[0007] A fourth aspect of the invention provides a step according to the first to third aspects, wherein the second radial end portion includes a radially inwardly extending protrusion.

[0008] A fifth aspect of the invention provides a stage according to the first to fourth aspects, wherein the post is a first post and a second post connects the first ring to the second ring.

[0009] A sixth aspect of the invention provides a step according to the first to fifth aspects, wherein the second post is disposed at a position of 180 degrees relative to the first post.

[0010] A seventh aspect of the invention provides a stage according to the first to sixth aspects, wherein the column includes an upper surface angled along the axial direction.

[0011] An eighth aspect of the invention provides a stage according to the first to seventh aspects, wherein the column is configured to mimic the hydraulic profile of a flow channel in the upstream portion of the housing of the multistage pump.

[0012] A ninth aspect of the invention provides a step according to the first to eighth aspects, wherein the first ring, the second ring, and the column are integrally formed as one piece.

[0013] The tenth aspect of the invention provides a step according to the first to ninth aspects, wherein the first ring, the second ring and the post are cast as a single piece.

[0014] An eleventh aspect of the present invention provides a multistage pump comprising: a pump housing defining a flow passage; a shaft rotatably disposed within the pump housing and having a longitudinal axis; a first impeller disposed within the housing at a first position along the shaft; a second impeller disposed within the housing at a second position along the shaft; and a stage member disposed in the flow passage and including a first ring, a second ring, and a post connecting the first ring to the second ring, the post having a first radial end and a second radial end, and a first side and a second side connecting the first and second ends, the first and second sides being arcuate and extending toward each other such that the first radial end is longer than the second radial end.

[0015] The twelfth aspect of the invention provides a multi-stage pump according to the eleventh aspect, wherein the first radial end is arc-shaped.

[0016] The thirteenth aspect of the invention provides a multistage pump according to the eleventh or twelfth aspect, wherein the second radial end extends radially inside the first and second rings.

[0017] The fourteenth aspect of the invention provides a multi-stage pump according to aspects eleven to thirteen, wherein the second radial end includes a radially inwardly extending protrusion.

[0018] The fifteenth aspect of the invention provides a multi-stage pump according to aspects eleven through fourteen, wherein the column is a first column and a second column connects the first ring to the second ring.

[0019] The sixteenth aspect of the invention provides a multi-stage pump according to aspects eleven to fifteen, wherein the second column is disposed at a 180-degree position relative to the first column.

[0020] The seventeenth aspect of the invention provides a multi-stage pump according to aspects eleven through sixteen, wherein the column includes an upper surface angled along the axial direction.

[0021] The eighteenth aspect of the invention provides a multistage pump according to aspects eleven through seventeen, wherein the column is configured to mimic the hydraulic profile of a flow channel in the upstream portion of the housing of the multistage pump.

[0022] The nineteenth aspect of the invention provides a multi-stage pump according to aspects eleven to eighteen, wherein the first ring, the second ring, and the column are integrally formed as one piece.

[0023] The twentieth aspect of the invention provides a multi-stage pump according to aspects eleven through nineteen, wherein the first ring, the second ring, and the column are cast as a single piece.

[0024] These aspects of the invention provide an improved bridging stage that is more efficient and thus saves energy. Furthermore, the two-column design, shaped to mimic the hydraulic profile of the flow channel in the upstream portion of the assembly, limits efficiency losses by better directing flow to the inlet of the downstream impeller, which saves energy.

[0025] Embodiments of the present invention can also be substantially thicker than previous designs and better suited to the metal flow between the two rings during the casting process. Therefore, embodiments of the present invention can save on rework and scrap after production. Attached Figure Description

[0026] Now refer to the accompanying drawings that form part of this original disclosure:

[0027] Figure 1 This is a top perspective view of a multi-stage pump including bridging stages according to an embodiment of the present invention;

[0028] Figure 2 yes Figure 1 A cross-sectional view of a multistage pump;

[0029] Figure 3 yes Figure 1 A partial cross-sectional view of a multistage pump, showing the bridging stage;

[0030] Figure 4 yes Figure 3 Top perspective view of the bridging stage;

[0031] Figure 5 yes Figure 3 Side perspective view of the bridging stage component;

[0032] Figure 6 yes Figure 3 A top view of the bridging stage components;

[0033] Figure 7 yes Figure 3 Side view of the bridging stage component;

[0034] Figure 8 It is in the housing of the multistage pump Figure 3 A cross-sectional perspective view of the bridging stage component;

[0035] Figure 9 yes Figure 8 An enlarged view of the bridging stage shown;

[0036] Figure 10 yes Figure 9 The front view of the bridging stage shown;

[0037] Figure 11 It is in the housing of the multistage pump Figure 3 A cross-sectional perspective view of the bridging stage; and

[0038] Figure 12 yes Figure 11 An enlarged view of the bridging stage shown. Detailed Implementation

[0039] Selected embodiments will now be explained with reference to the accompanying drawings. It will be apparent to those skilled in the art from this disclosure that the following description of the embodiments is provided for illustrative purposes only and is not intended to limit the invention as defined by the appended claims and their equivalents.

[0040] First refer to Figures 1 to 3 The first embodiment shows a multistage pump 1 including a stage piece 10. The multistage pump 1 includes a cylindrical pump housing (or shell) 16, the stage piece 10, an impeller shaft 26, a first impeller 28, and a second impeller 30.

[0041] Housing 16 includes: a pump inlet 18 through which multi-stage process fluid enters pump 1 at the low-pressure side LP; and a pump outlet 20 for discharging the process fluid at an elevated pressure at the high-pressure side HP, as indicated by the arrow. Typically, pump outlet 20 is connected to a pipe or piping system (not shown) for delivering the process fluid to another location. The pressure of the process fluid at pump outlet 20 (i.e., the high-pressure side HP) is typically significantly higher than the pressure of the process fluid at pump inlet 18 (i.e., the low-pressure side LP). A typical value for the difference between the high-pressure and low-pressure sides is, for example, 50 to 200 bar.

[0042] The housing 16 is a separate "staged" housing 16 having several stages 22, capable of withstanding the pressure generated by the multistage pump 1 and the pressure applied to the multistage pump 1 by the environment. Each stage 22 comprises several different housing portions connected to each other to form the housing 16. Thus, the several stages 22 may include a high-pressure stage 22a disposed at the pump outlet 20 on the high-pressure side HP, a low-pressure stage 22b disposed at the pump inlet 18 on the low-pressure side LP, and any number of desired stages. Figure 1 An embodiment with eleven (11) segments is shown; however, it should be noted that more or fewer segments may be present as desired. The segments 22 are arranged in series and are configured to form a low-pressure segment 22b and a high-pressure segment 22a. The low-pressure segment 22b may be an intake housing, and the high-pressure segment 22a may be an exhaust housing.

[0043] The multistage pump 1 further includes a pump rotor that rotates about an axial or longitudinal direction A during the operation of the multistage pump 1. As can be understood, the pump rotor delivers process fluid from the inlet 18 at the low-pressure side LP to the pump outlet 20 (i.e., the discharge section) at the high-pressure side HP.

[0044] The pump rotor includes a shaft 26 rotatable about an axial direction A and a plurality of impellers (e.g., a first impeller 28 and a second impeller 30 in one embodiment), the plurality of impellers being arranged in series along the axial direction A for conveying process fluid from an inlet 18 to an outlet 20, and thereby increasing the pressure of the process fluid. The shaft 26 is rotatably disposed within a pump housing 16, and the first impeller 28 is disposed in a first position within the housing 16 along the shaft 26, and the second impeller is disposed in a second position within the housing 16 along the shaft 26.

[0045] A drive motor can be used to rotate the pump rotor shaft 26. In some embodiments, the motor may be a separate unit located outside the pump housing 16. In other embodiments, the motor may be integrated into the housing 16.

[0046] like Figure 3 As shown, the bridging stage 10 is disposed within the housing in the flow path of the multistage pump 1. In one embodiment, multiple bridging stages 10 are disposed within the housing in the flow path of the multistage pump 1.

[0047] The bridging stage 10 includes a first ring 34, a second ring 36, and a post 38 connecting the first ring 34 to the second ring 36. The post 38 has a first radial end and a second radial end, and a first side and a second side connecting the first and second ends. The first and second sides are arcuate and extend toward each other, such that the first radial end is longer than the second radial end.

[0048] like Figure 4-12As shown, the bridging stage 10 is preferably a single piece. That is, in one embodiment, the first ring 34, the second ring 36, and the post 38 are integrally formed as one piece. In one embodiment, the bridging stage 10 is cast as a single piece. That is, in one embodiment, the first ring 34, the second ring 36, and the post 38 are cast as a single piece.

[0049] The cast column 38, along with the first and second rings 34 and 36, avoids many problems associated with conventional designs. Specifically, it has been found that in conventional designs, columns require a thin cross-section to attempt to avoid flow disturbance. This thin cross-sectional structure of conventional columns makes them difficult to cast without crack propagation. As described herein, column 38 is substantially thicker and better suited to the flow of metal between the two rings during the casting process. Therefore, forming column 38, as described herein, can save on rework and scrap after production.

[0050] Furthermore, if repeated attempts to cast a conventional column design fail, the component will typically have to be fabricated by welding, which can increase costs by three or four times. Column 38 avoids such problems due to the construction described herein. Casting is also the preferred method because it allows for a wider range of available metallurgical options for the bridging stage 10. Fabrication of dissimilar metals can be extremely difficult. However, it should be noted that any suitable material can be used.

[0051] The first and second rings 34 and 36 each have an outer circumferential surface 40 and an inner surface 42. The inner surface defines an opening or through-passage 44. The inner and outer surfaces 40 and 42 of the first and second rings 34 and 36 are generally parallel, such that the first and second rings 34 and 36 overlap. In other words, when viewed in the axial or longitudinal direction, the first and second rings 34 and 36 occupy approximately the same or similar positions.

[0052] A post 38 is disposed between the first ring 34 and the second ring 36. That is, the post 38 extends from the inner axial surface 46 of the first ring 34 to the inner axial surface 46 of the second ring 36 to connect the first ring 34 to the second ring 36. As described herein, preferably, the post 38 is cast together with the first and second rings 34 and 36 to form an integral one-piece component; however, the post 38 may be connected to the first and second rings 34 and 36 in any desired manner.

[0053] The column 38 has a first radial or outer circumferential end 48, a second radial or inner circumferential end 50, a first side surface 52, a second side surface 54, and an upper side surface or upper surface 56. In one embodiment, the first radial end 48 is arcuate, and the second radial end 50 extends radially inward of the first and second rings 34 and 36. Figure 4 As shown, the second radial end portion 50 may include a stepped portion or a radially inwardly extending protrusion 58.

[0054] First side surface 52 and second side surface 54 extend between first radial end 48 and second radial end 50. The first and second side surfaces 52 and 54 extend generally radially and are arcuate. That is, each of the first and second side surfaces 52 and 54 has an inwardly curved configuration and is configured to narrow the post 38 radially inward. Therefore, the first and second side surfaces 52 and 54 extend toward each other such that the first radial end 48 is longer than the second radial end 50. The upper surface 56 is angled along the axial direction A. Additionally, in one embodiment, the upper surface 56 has a curved configuration as it extends from the first ring 34 to the second end 50. The upper surface 56 is disposed between the first side surface 52 and the second side surface 54, and thus narrows radially inward toward the second end 50.

[0055] like Figure 4 As shown, the second end portion 50 extends substantially from the upper surface 56 to the inner surface 42 of the second ring 36. Extending from the upper surface 56, the second end portion 50 has a surface 62 that is radially outwardly angled in a direction transverse to the axial direction A. The surface 64 of the second end portion 50 extends substantially perpendicular to the axial direction A (i.e., in the radial direction). The surface 66 of the second end portion 50 extends substantially perpendicular to the radial direction (i.e., in or parallel to the axial direction A), thereby forming a stepped portion or a radially inwardly extending protrusion 58 until the second end portion connects to the second ring 36.

[0056] In one embodiment, the first and second rings 34 and 36 are connected by two posts 38. The two posts 38 may have the same (albeit) mirror image construction. The second post 38 may be positioned 180 degrees relative to the first post 38 between the first ring 34 and the second ring 36. It should be noted that the rings may be connected by any number of posts (including one), and are not limited to two posts.

[0057] The column construction disclosed herein can mimic the hydraulic profile (volute casing) of the flow channel in the upstream portion of the housing 16 of a multistage pump 1. Therefore, the aforementioned column structure limits efficiency losses by effectively guiding the flow to the inlet of the downstream impeller, thereby saving energy.

[0058] Furthermore, in one embodiment, the invention has two posts 38. This differs from conventional devices, which typically have four bridging posts connecting two rings. Two of the four conventional posts would inherently be positioned in the flow path, resulting in a reduction in the overall efficiency of the pump. Therefore, this embodiment of the invention improves the overall efficiency of the pump.

[0059] General Explanation of Terms

[0060] In understanding the scope of this invention, the term "comprising" and its derivatives, as used herein, are intended to be open-ended terms that specify the presence of the stated features, elements, components, groups, integers, and / or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers, and / or steps. The foregoing also applies to words with similar meanings, such as the terms "comprising," "having," and their derivatives.

[0061] As used herein to describe a component, section, or part of a device, the term "constructed" includes hardware and / or software constructed and / or programmed to perform the desired function.

[0062] As used in this paper, degree terms (such as “basically,” “about,” and “approximately”) indicate a reasonable amount of deviation of the term being modified such that the final result does not change significantly.

[0063] Although only selected embodiments have been chosen to illustrate the invention, it will be apparent to those skilled in the art, based on this disclosure, that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. For example, the size, shape, position, or orientation of various components can be varied as needed and / or desired. Components shown as being directly connected or in contact with each other may have an intermediate structure between them. The function of one element may be implemented by two elements, and vice versa. The structure and function of one embodiment may be used in another embodiment. Not all advantages are necessarily present in a particular embodiment. Each feature that differs from the prior art (alone or in combination with other features) should also be considered as a separate description by the applicant of further inventions, including structural and / or functional concepts implemented by such features. Therefore, the foregoing description of embodiments of the invention is provided for illustrative purposes only and is not intended to limit the invention as defined by the appended claims and their equivalents.

Claims

1. A stage component for a multi-stage pump, comprising: First ring (34); Second ring (36); as well as The first ring (34) is connected to the first and second posts (38) of the second ring (36), each of the first and second posts (38) having a first radial end (48) and a second radial end (50) and a first side (52) and a second side (54) connecting the first and second ends (48, 50). The first and second sides (52, 54) are arcuate and extend toward each other, such that the first radial end (48) is longer than the second radial end (50).

2. The stage component according to claim 1, wherein, For each of the first and second pillars (38), the first radial end (48) is arc-shaped.

3. The stage component according to claim 1, wherein, For each of the first and second pillars (38), the second radial end (50) extends radially inside the first and second rings (34, 36).

4. The stage component according to claim 1, wherein, For each of the first and second pillars (38), the second radial end (50) includes a radially inwardly extending protrusion (58).

5. The stage component according to claim 1, wherein, The second column (38) is positioned at a 180-degree angle relative to the first column (38).

6. The stage component according to claim 1, wherein, For each of the first and second pillars (38), the pillar (38) includes an upper surface (56) angled in the axial direction.

7. The stage component according to claim 1, wherein, Each of the first and second columns (38) is configured to mimic the hydraulic profile of a flow channel in the upstream portion of the housing of the multistage pump.

8. The stage component according to claim 1, wherein, The first ring, the second ring, the first pillar (38) and the second pillar (38) form a single terrain feature.

9. The stage component according to claim 1, wherein, The first ring, the second ring, the first post (38), and the second post (38) are cast as one piece.

10. A multistage pump, comprising: Pump housing (16), the pump housing defining a flow passage; Shaft (26), which is rotatably disposed within the pump housing (16) and has a longitudinal axis; A first impeller (28) is disposed within the housing (16) at a first position along the shaft (26); A second impeller (30) is disposed in the housing (16) at a second position along the shaft (26); as well as A stage (10) is disposed in the flow channel and constructed according to any one of the preceding claims.

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