Multi-stage pump

Abstract

A multi-stage pump includes a pump housing, a shaft, a first impeller, a second impeller, and a tube. The shaft is rotatably disposed within the pump housing and has a longitudinal axis. The first impeller is disposed within the housing at a first location along the shaft. The second impeller is disposed within the housing at a second location and along the shaft. The tube is detachably attached to the pump housing and has an inlet and an outlet, the inlet disposed at a discharge of the first impeller and the outlet disposed at an intake of the second impeller such that a discharge from the first impeller can be delivered to the intake of the second impeller.

Description

TECHNICAL FIELD

[0001] The present invention relates generally to a multi-stage pump. In particular, the present invention relates to a tube for a multi-stage pump. BACKGROUND

[0002] Conventional multi-stage pumps or multi-stage double volute pumps typically include opposing impeller designs. The opposing impellers are arranged facing in opposite directions so as to balance the axial thrust generated by the rotating elements. A crossover passage carries product from the discharge of the intermediate stage impeller to the distal side of the pump and into the inlet of the subsequent opposing stage impeller. In conventional multi-stage pumps, the crossover passage is integrally formed with the pump housing and is rectangular or trapezoidal in cross-section. SUMMARY

[0003] It has been found that in conventional multi-stage pumps, the length of the passage in combination with a small cross-sectional area (particularly low specific speed) presents difficulties at foundries. These passages can require special windows cut into the casting to enable the cleaning and removal of sand inclusion, partial blockage, core wire, and debris. The requirement of this cleaning process increases the cost and time of the casting process. Furthermore, if the passages are not effectively cleaned, partially obstructed passages or poor surface quality can adversely affect pump performance. To improve the operation of multi-stage pumps, it is desirable to have a new crossover and / or a new crossover tube.

[0004] In view of the state of the known art, a first aspect of the present disclosure provides a multi-stage pump comprising a pump housing, a shaft, a first impeller, a second impeller, and a tube. The shaft is rotatably disposed within the pump housing and has a longitudinal axis. The first impeller is disposed within the housing at a first location along the shaft. The second impeller is disposed within the housing at a second location and along the shaft. The tube is detachably attached to the pump housing and has an inlet and an outlet, the inlet being disposed at a discharge of the first impeller and the outlet being disposed at an inlet of the second impeller such that a discharge from the first impeller can be carried to the inlet of the second impeller.

[0005] A second aspect of the present invention provides the multi-stage pump of the first aspect, wherein the tube is formed separately from the pump housing.

[0006] A third aspect of the present invention provides the multi-stage pump of the first or second aspect, wherein the tube is configured to be bolted to the pump housing.

[0007] A fourth aspect of the present invention provides the multi-stage pump of any one of the first through third aspects, wherein the tube has a substantially circular internal cross-section.

[0008] A fifth aspect of the present invention provides the multi-stage pump of any one of the first through fourth aspects, wherein the multi-stage pump has 11 stages.

[0009] A sixth aspect of the application provides the multi-stage pump of any one of the first to fifth aspects, wherein the multi-stage pump has 4 stages.

[0010] A seventh aspect of the application provides the multi-stage pump of any one of the first to sixth aspects, wherein the tube is a crossover tube, and the multi-stage pump includes a jumper tube removably attached to the pump housing.

[0011] An eighth aspect of the application provides the multi-stage pump of any one of the first to seventh aspects, wherein the tube is a jumper tube, and the multi-stage pump includes a crossover tube removably attached to the pump housing.

[0012] A ninth aspect of the application provides the multi-stage pump of any one of the first to eighth aspects, wherein the tube rotates away from the longitudinal axis.

[0013] A tenth aspect of the application provides a tube for a multi-stage pump, comprising: a first end having an inlet and configured to be removably attached to a housing at a first location at a discharge of a first impeller disposed within the pump housing; and a second end having an outlet and configured to be removably attached to the housing at a second location at an intake of a second impeller, such that a discharge from the first impeller can be conveyed through the tube from the outlet of the first impeller to the intake of the second impeller.

[0014] An eleventh aspect of the application provides the tube of the tenth aspect, wherein the tube is configured to be formed separately from the housing.

[0015] A twelfth aspect of the application provides the tube of the tenth or eleventh aspect, wherein the first and second ends of the tube are configured to be bolted to the pump housing.

[0016] A thirteenth aspect of the application provides the tube of any one of the tenth to twelfth aspects, wherein the tube has a substantially circular internal cross-section.

[0017] A fourteenth aspect of the application provides the tube of any one of the tenth to thirteenth aspects, wherein the tube is a crossover tube.

[0018] A fifteenth aspect of the application provides the tube of any one of the tenth to fourteenth aspects, wherein the tube is a jumper tube.

[0019] A sixteenth aspect of the application provides the tube of any one of the tenth to fifteenth aspects, wherein the tube is configured to rotate away from a longitudinal axis of the pump.

[0020] These aspects of the invention provide an improved jumper or through-tube with significant advantages over conventional access methods. For example, embodiments of the invention allow for a smaller cross-section than conventional jumpers. This smaller cross-section is possible due to the inherent precision of the inner surface of a standard tube, whereas the surface of an integrated jumper is subject to undulations and imperfections, which are typically compensated for by a larger nominal cross-section. Furthermore, embodiments of the invention can reduce hydraulic losses. This reduction in hydraulic losses is typically based on the roughness of the inner surface of the tube, and the roughness of the inner surface of the tube of the invention is significantly improved compared to standard finishing.

[0021] Furthermore, this invention provides freedom in positioning the volute end and the dumping end. The hydraulic design of bridging components is constrained by manufacturing and weight requirements, which can be relaxed in the case of external pipes. For example, in conventional pathways, long bridging / penetrating channels must be close to the body of the housing for shaping and quality optimization, which translates into highly curved pathways with associated hydraulic losses.

[0022] Furthermore, computational fluid dynamics (CFD) can be used to optimize and validate the 3D-generated hydraulics associated with embodiments of the present invention. Attached Figure Description

[0023] Now refer to the accompanying drawings that form part of this original disclosure:

[0024] Figure 1 This is a top perspective view of one embodiment of a multistage pump including tubing;

[0025] Figure 2 yes Figure 1 A front perspective view of a multistage pump;

[0026] Figure 3 yes Figure 1 Rear perspective view of a multistage pump;

[0027] Figure 4 yes Figure 1 Left side view of a multistage pump;

[0028] Figure 5 yes Figure 1 Right side view of a multistage pump;

[0029] Figure 6 yes Figure 1 Bottom view of a multistage pump;

[0030] Figure 7 yes Figure 1 Front view of a multistage pump;

[0031] Figure 8 yes Figure 1 A top view of a multistage pump;

[0032] Figure 9 is a cross-sectional view taken along line 9-9 of Figure 3

[0033] Figure 10 is a cross-sectional view taken along line 10-10 of Figure 3

[0034] Figure 11 is a cross-sectional view taken along line 11-11 of Figure 7

[0035] Figure 12 is a top perspective view of a second embodiment of a multi-stage pump including a tube;

[0036] Figure 13 is a front perspective view of the multi-stage pump of Figure 12

[0037] Figure 14 is a rear perspective view of the multi-stage pump of Figure 12

[0038] Figure 15 is a left side view of the multi-stage pump of Figure 12

[0039] Figure 16 is a right side view of the multi-stage pump of Figure 12

[0040] Figure 17 is a bottom view of the multi-stage pump of Figure 12

[0041] Figure 18 is a front view of the multi-stage pump of Figure 12

[0042] Figure 19 is a top view of the multi-stage pump of Figure 12

[0043] Figure 20 is a cross-sectional view taken along line 20-20 of Figure 14

[0044] Figure 21 is a cross-sectional view taken along line 21-21 of Figure 13

[0045] Figure 22 is a cross-sectional view taken along line 22-22 of Figure 13

[0046] Figure 23 is a cross-sectional view taken along line 23-23 of Figure 15 DETAILED DESCRIPTION​​​​​​​​​​​​​​

[0047] Selected embodiments will now be explained with reference to the drawings. It will be readily understood to those skilled in the art that the following description of the embodiments is only illustrative of the present application and is not intended to be limiting.

[0048] Reference is first made to Figure 1 According to a first embodiment, a multi-stage pump 10 is shown that includes a crossover pipe 12 and a jumper pipe 14. In particular, the multi-stage pump 10 includes a cylindrical pump housing (or shell) 16, an impeller shaft, a first impeller 28, a second impeller 30, the crossover pipe 12, and the jumper pipe 14.

[0049] The housing 16 includes a pump inlet 18 through which a multi-stage process fluid enters the pump at a low pressure side LP as indicated by the arrow, and a pump outlet 20 for discharging the process fluid at an elevated pressure at a high pressure HP side as indicated by the arrow. Typically, the 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 the pump outlet 20 (i.e., at the high pressure side HP) is typically significantly higher than the pressure of the process fluid at the pump inlet 18 (i.e., at the low pressure side LP). Typical values of the difference between the high pressure HP and the low pressure LP side are, for example, from about 50 bar to about 200 bar.

[0050] The housing 16 is a separate "staged" housing 16 having a number of stages 22 that can withstand the pressures generated by the multi-stage pump 10 as well as the pressures exerted on the multi-stage pump 10 by the environment. The stages 22 include a number of different housing portions that are connected to each other to form the housing 16. As such, the number of stages 22 can include a high pressure stage 16a disposed on the high pressure HP side at the pump outlet 20, a low pressure stage 16b disposed on the low pressure LP side at the pump inlet 18, and any number of desired stages. Figures 1-11 An embodiment is shown having eleven (11) stages, and Figures 12-23 An embodiment is shown having four (4) stages; however, it should be noted that more or less stages can be present as desired. The stages 22 are arranged in series and are arranged between the low pressure stage 16b and the high pressure stage 16a. The low pressure stage 16b can be a suction housing and the high pressure stage 16a can be a discharge housing.

[0051] The multi-stage pump 10 further includes a pump rotor that rotates about the axial or longitudinal direction A in an operating state of the multi-stage pump 10. As can be appreciated, the pump rotor transports the process fluid from the inlet annulus at the low pressure side LP to the discharge annulus at the high pressure side HP.

[0052] 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) arranged in series along the axial direction A for transporting the process fluid from the inlet 18 to the outlet 20 and thereby increasing the pressure of the process fluid. The shaft 26 is rotatably disposed within the pump housing 16 and the first impeller 28 is disposed within the housing 16 at a first location along the shaft 26 and the second impeller 30 is disposed within the housing 16 at a second location and along the shaft 26.

[0053] A drive motor can be used to rotate the shaft 26 of the pump rotor. In some embodiments, the motor can be a separate unit located outside of the housing 16 of the pump. In other embodiments, the motor can be integrated into the housing 16.

[0054] The crossover pipe 12 crosses the upper side of the housing 16 and is removably attached to the pump housing 16. The crossover pipe 12 has an inlet 12a and an outlet 12b. The inlet 12a is disposed at the discharge of the first impeller 28 and the outlet 12b is disposed at the inlet of the second impeller 30 so that the discharge from the first impeller 28 can be transported to the inlet of the second impeller 30. The crossover pipe 12 is formed separately from the pump housing 16 and is configured to be bolted to the pump housing 16. In one embodiment, the pipe crossover pipe 12 is attached to the pump housing 16 using a blocking flange 32. The blocking flange 32 enables a reduction in size relative to a conventional flange such that the flange size is not a major feature of the outer surface of the housing. As can be appreciated, the housing is significantly lighter and easier to shape and machine relative to conventional pipe flanges used for bolting on pipes. Thus, the blocking flange 32 is critical to the compactness of the design of the housing 16.

[0055] As Figure 9 and Figure 10As shown in FIG. 1, the crossover pipe 12 is attached to the housing at the first end 34 by a first blocking flange 32a. The first blocking flange 32a is a rectangular or square flange and is attached (or integrally molded) to the first end 34 of the pipe 12. The blocking flange 32a is coupled to a corresponding block 36 molded into the housing 16 using bolts or in any other suitable manner. The crossover pipe 12 is a generally tubular pipe extending from the blocking flange 32a generally transverse to the longitudinal axis A of the housing 16. The pipe 12 is then bent so as to extend parallel (or substantially parallel) to the longitudinal direction A along the housing 16. The pipe 12 is then bent inwardly toward the housing and extends in a direction generally transverse to the longitudinal axis A of the housing 16. The second end 38 of the pipe 12 is attached to the housing 16 at the second end 36 by a second blocking flange 32b. The second blocking flange 32b is a rectangular or square flange attached (or integrally molded) to the second end 38 of the pipe 12. The second blocking flange 32b is coupled to a corresponding block 40 molded into the housing 16 using bolts or in any other suitable manner. The crossover pipe 12 can have a generally circular internal cross-section or any other suitable cross-section. In one embodiment, the crossover pipe 12 is rotated away from the longitudinal axis.

[0056] The crossover pipe 14 crosses over the underside of the housing 16 and is removably attached to the pump housing 16. The crossover pipe 14 has an inlet 14a and an outlet 14b. The inlet 14a is disposed at the discharge of the first impeller 28 and the outlet 14b is disposed at the inlet of the second impeller 30 so that the discharge from the first impeller 28 can be delivered to the inlet of the second impeller 30. The crossover pipe 14 is formed separately from the pump housing 16 and is configured to be bolted to the pump housing 16. In one embodiment, the pipe crossover pipe 14 is attached to the pump housing 16 using a blocking flange 32. The blocking flange 32 enables a reduction in size relative to conventional flanges so that the flange size is not a major feature of the outer surface of the housing. As can be appreciated, the housing 16 is significantly lighter and easier to shape and machine relative to conventional pipe flanges used for bolting on pipes. Thus, the blocking flange 32 is critical to the compactness of the design of the housing 16.

[0057] As Figure 9 and Figure 10As shown in the middle, the crossover pipe 14 is attached to the housing 16 at the first end 42 by a first blocking flange 32c. The first blocking flange 32c is a rectangular or square flange that is attached (or integrally molded) to the first end 42 of the pipe 14. The blocking flange 32 is coupled to a corresponding block 44 that is molded into the housing 16 using bolts or in any other suitable manner. The crossover pipe 14 is a generally tubular pipe that extends generally transverse to the longitudinal axis A of the housing from the blocking flange 32c. The pipe 14 is then bent so as to extend along the housing 16 parallel to the longitudinal direction A. The pipe 14 is then bent inwardly toward the housing 16 and extends in a direction that is generally transverse to the longitudinal axis A of the housing 16. The second end 44 of the pipe 14 is attached to the housing 16 at the second end 44 by a second blocking flange 32d. The second blocking flange 32d is a rectangular or square flange that is attached (or integrally molded) to the second end 44 of the pipe 14. The second blocking flange 32d is coupled to a corresponding block 46 that is molded into the housing using bolts or in any other suitable manner. The crossover pipe 14 can have a generally circular internal cross-section or any other suitable cross-section. In one embodiment, the crossover pipe 14 is rotated away from the longitudinal axis.

[0058] As can be appreciated, the blocking flanges 32 disclosed herein are formed simultaneously with the pipes 12 and 14, such that the first and second blocking flanges are integral with the pipes. However, if desired, the blocking flanges 32 can be formed separately from the pipes 12 and 14 and coupled thereto using any desired coupling. For example, the blocking flanges 32 can be coupled to the pipes 12 and 14 by welding, bolts or any other suitable connection. Additionally, the blocking flanges 32 are preferably formed from the same material as the pipes 12 and 14; however, the blocking flanges 32 can be formed from a different material.

[0059] It goes without saying that the multi-stage pump 10 according to the application can be designed as a vertical or horizontal pump, wherein the pump rotor extends in a vertical or horizontal direction, respectively, i.e. perpendicular to the direction of gravity.

[0060] As can be appreciated, the fluid flow exits the pre-cross-over (upstream) impeller (first impeller 28) and is split in two passages by the axially split volute housing. Half of the total flow travels through the crossover and half of the flow travels through the crossover. That is, half of the flow enters the first end 34 of the crossover pipe 12 at the inlet 12a and half of the flow enters the first end 42 of the crossover pipe 14 at the inlet 14a.

[0061] From there, both flow halves flow through the respective pipes (crossover pipe 12 and crossover pipe 14) and exit the respective pipes at the respective second ends (38 and 44) through the outlets (12b and 14b). The flow then enters the dump and is redirected 180 degrees back on course and recombined into a single flow path that enters the downstream impeller inlet (second impeller 30).

[0062] Figures 12-23 A second embodiment of a multi-stage pump 110 having four (4) stages is shown. In this embodiment, similar elements are denoted with the same reference numerals as in the first embodiment and are not further described. In the second embodiment, the casing 116 is a separate "staged" casing 116 having several stage segments 122 capable of withstanding the pressure generated by the multi-stage pump 10 as well as the pressure exerted on the multi-stage pump 10 by the environment. The stage segments 122 comprise several different casing portions that are connected to each other to form the casing 116. As such, the several stage segments 122 can comprise a high pressure segment 116a disposed on the high pressure HP side at the pump outlet 20, a low pressure segment 116b disposed on the low pressure LP side at the pump inlet 18. Figures 12-23 An embodiment having four (4) stages is shown; however, it should be noted that more or less stages can be present as desired. The stage segments 122 are arranged in series and between the low pressure segment 116b and the high pressure segment 116a. The low pressure segment 116b can be a suction casing and the high pressure segment 116a can be a discharge casing.

[0063] The drive motor is a conventional component well known in the art. As the drive motor is well known in the art, this structure will not be discussed or shown in detail herein. Rather, it will be apparent to those skilled in the art from this disclosure that the component can have any type of structure that can be used to perform the present application.

[0064] As described herein, by providing a crossover pipe 12 and / or a jumper pipe 14, the multi-stage pump 10 can have a small cross section, i.e., a smaller size than conventional crossovers. For example, the inner diameter cross section can be up to about 50% of the channel formed internally. This smaller cross section is possible due to the inherent precision of the inner surface of a standard pipe, whereas the surface of an integrated crossover is subject to undulations and imperfections that are typically compensated for by a larger nominal cross section. The crossover pipe 12 and jumper pipe 14 described herein can reduce hydraulic losses as the roughness of the inner surface of the pipe is significantly improved compared to standard finishings.

[0065] The crossover pipe 12 and jumper pipe 14 described herein provide more degrees of freedom for the positioning of the volute end and the dump end. The hydraulic design of a classic crossover is subject to manufacturing and weight requirements that can be relaxed for the crossover pipe 12 and jumper pipe 14 described herein. As can be appreciated, a conventional long crossover / jumper channel must be close to the body of the casing 16 for shaping and mass optimization, which translates into a highly curved passage with associated hydraulic losses. The present application overcomes such problems.

[0066] The present invention can also optimize and maintain associated 3D generated hydraulics through computational fluid dynamics (CFD). The present invention can simplify the shell pattern setup as long jumper / penetrator cartridges are not required. In some embodiments, the present invention can use commercially available pipes and fittings and use compact custom blocking (attachment) flanges to minimize the interface area with the outer shell 16.

[0067] Further, in the present invention, the developed length of the pipes 12 and 14 can be adjusted to mitigate any potential issues with acoustic resonance and the bolted attachment to the outer shell 16 eliminates the issues of stress with improper welding, heat treatment, and non-destructive testing requirements compared to welded joints.

[0068] Also, the jumper / penetrator pipes 12 and 14 described herein can be rotated away from the vertical centerline which reduces the overall height of the outer shell 16 resulting in a more compact design.

[0069] General interpretation of terms

[0070] In understanding the scope of the present 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 like- meaning terms, such as “comprises,” “have,” “has,” and “including,” and their derivatives.

[0071] The term “configured” as used herein to describe a component, section or portion of a device includes hardware and / or software configured and / or programmed to perform a desired function.

[0072] The degree terms (e.g., “substantially,” “about,” and “approximately”) as used herein refer to a reasonable variation that does not significantly change the end result.

[0073] While only selected embodiments have been chosen for illustration, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made and that other embodiments can be used without departing from the scope of the application as defined by the appended claims. For instance, variations in sizes, shapes, and / or orientations of the components, and / or variations in positions of interconnections of the components could be made and still be within the scope of the application. Parts shown directly connected or contacting each other could be separated in between. The functionality of one element could be implemented by two, and / or the functionality of two elements could be implemented by one. The structure and function of one embodiment could be implemented in another embodiment. Not all advantages mentioned hereinbefore are necessarily present in one particular embodiment. Every feature which is unique from the state of the art, separately or in any combination, should be considered an embodiment of the application which is separately described by the Applicant for further invention. Therefore, the foregoing description of embodiments of the application is not intended to be exhaustive or to limit the application to the precise forms disclosed.

Claims

1. A multistage pump, comprising: Pump housing; A shaft, rotatably disposed within the pump housing and having a longitudinal axis; A first impeller is disposed within the housing at a first position along the shaft; A second impeller is located at a second position and disposed within the housing along the axis; as well as A crossover pipe and a through pipe are each detachably attached to the pump housing and each has an inlet and an outlet. The inlet is located at the discharge portion of the first impeller, and the outlet is located at the inlet of the second impeller, so that the discharge from the first impeller can be conveyed to the inlet of the second impeller. The volute housing is provided to separate the fluid flow leaving the first impeller, such that half of the fluid flow flows through the cross-connector and the other half of the fluid flow flows through the through-connector. The pump housing comprises several stages, each stage comprising several different housing parts connected to each other to form the pump housing.

2. The multistage pump according to claim 1, wherein, The cross-connector or the through-connector is formed separately from the pump housing.

3. The multistage pump according to claim 1, wherein, The cross-connector or the through-connector includes a blocking flange and is configured to be bolted to the pump housing via the blocking flange.

4. The multistage pump according to claim 1, wherein, The cross-connector or the through-connector has a generally circular internal cross-section.

5. The multistage pump according to claim 1, wherein, The multistage pump has 11 stages.

6. The multistage pump according to claim 1, wherein, The multistage pump has four stages.

7. The multistage pump according to claim 1, wherein, The cross-connector or the through-connector rotates away from the longitudinal axis.

8. A jumper or through-pipe for a multistage pump according to any one of claims 1-7, comprising: A first end, having an inlet and configured to be detachably attached to the housing at a first position where the discharge portion of a first impeller disposed within the pump housing is located; as well as The second end, having an outlet and configured to be detachably attached to the housing at a second position at the inlet of the second impeller, allows discharge from the first impeller to be conveyed from the outlet of the first impeller to the inlet of the second impeller via the cross-connector or the through-connector.

9. The cross-connector or through-connector according to claim 8, wherein, The cross-connector or the through-connector is configured to be formed separately from the housing.

10. The cross-connector or through-connector according to claim 8, wherein, The first and second ends of the cross-connector or the through-connector are configured to be bolted to the pump housing.

11. The cross-connector or through-connector according to claim 8, wherein, The cross-connector or the through-connector has a generally circular internal cross-section.

12. The cross-connector or through-connector according to claim 8, wherein, The cross-connector or the through-connector is configured to rotate away from the longitudinal axis of the pump.

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