Vertical multistage pump

Abstract

The present invention provides a vertical multi-stage pump comprising: a rotating shaft extending in a vertical direction; a plurality of impellers fixed to the rotating shaft; a multi-stage pump chamber accommodating the plurality of impellers and having a suction port for a first-stage impeller at a lower end; a lower casing having a suction nozzle extending in a horizontal direction to form a communicating space connecting the suction nozzle and the suction port; and an inner cylinder component sandwiched between the multi-stage pump chamber and the lower casing to expand the communicating space in the vertical direction.

Description

Technical Field

[0001] The present invention relates to a vertical multistage pump.

[0002] This application claims priority based on Japanese Patent Application No. 2019-175846 filed in Japan on September 26, 2019 and Japanese Patent Application No. 2019-175166 filed in Japan on September 26, 2019, and the contents of which are incorporated herein by reference. Background Art

[0003] The following patent document 1 Figure 1 Disclosed is a vertical multistage pump for use assembled midway in piping of fluid equipment. The vertical multistage pump comprises: a rotating shaft extending in a vertical direction; a plurality of impellers fixed to the rotating shaft; a multistage pump chamber housing the plurality of impellers and having a suction port for the first-stage impeller at its lower end; and a lower casing having a suction nozzle extending in a horizontal direction and forming a communication space connecting the suction nozzle and the suction port.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application No. 2017-531757 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] In such vertical multistage pumps, fluid drawn horizontally from the suction nozzle undergoes a roughly 90-degree change in flow path toward the suction port within the communicating space of the lower casing, immediately flowing into the impeller. This change in flow generates numerous vortexes. These vortexes impede fluid flow and cause fluid loss, reducing the pump's suction performance. Consequently, when the fluid is high-temperature water or when the pump is used at high altitude, fluid suction may be difficult.

[0009] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a vertical multi-stage pump capable of suppressing a decrease in the suction performance of the pump.

[0010] Means for solving problems

[0011] A vertical multistage pump according to one embodiment of the present invention comprises: a rotating shaft extending in a vertical direction; a plurality of impellers fixed to the rotating shaft; a multistage pump chamber accommodating the plurality of impellers and having a suction port for a first-stage impeller at a lower end; a lower casing having a suction nozzle extending in a horizontal direction, forming a communication space connecting the suction nozzle and the suction port; and an inner cylinder member sandwiched between the multistage pump chamber and the lower casing for expanding the communication space in the vertical direction.

[0012] The vertical multi-stage pump may further include an annular wall that protrudes inwardly of the inner cylinder member relative to a peripheral wall of the inner cylinder member.

[0013] Furthermore, in the vertical multi-stage pump, the center of the inner edge of the annular wall may be eccentric with respect to the center of the suction port.

[0014] Furthermore, the vertical multi-stage pump may further include a cylindrical guide portion extending vertically from a lower end opening of the inner cylindrical member to the suction port.

[0015] Furthermore, the vertical multi-stage pump may further include a flow rectifying grid provided inside the cylindrical guide portion.

[0016] Furthermore, in the vertical multi-stage pump, the center of the cylindrical guide portion may be eccentric with respect to the center of the suction port.

[0017] In addition, it is also possible that, based on the above-mentioned vertical multi-stage pump, there is provided: a first anti-rotation plate, which extends radially toward the center axis of the rotating shaft in the communicating space of the lower shell; and a second anti-rotation plate, which extends radially toward the center axis of the rotating shaft on the inner side of the inner cylinder component.

[0018] A vertical multistage pump according to one embodiment of the present invention comprises: a rotating shaft extending in a vertical direction; a plurality of impellers fixed to the rotating shaft; a multistage pump chamber accommodating the plurality of impellers and having a first suction port for a first-stage impeller at a lower end; and a lower casing having a suction nozzle extending in a horizontal direction, forming a communication space connecting the suction nozzle and the first suction port, wherein the first suction port is formed to be larger than the second suction port of the impellers from the second stage onward.

[0019] The vertical multi-stage pump may further include a rotation preventing plate extending radially toward the central axis of the rotating shaft in the communication space.

[0020] Furthermore, the vertical multistage pump may further include a raised portion raised on the bottom surface of the communication space in a conical shape centered on the rotation axis.

[0021] Furthermore, the vertical multi-stage pump may further include a guide portion that is disposed on an extension line of the suction nozzle in the communication space and that curves upward in a horizontal direction.

[0022] Furthermore, in the vertical multi-stage pump, the outlet diameter of the suction nozzle may be larger than the inlet diameter of the suction nozzle.

[0023] Effects of the Invention

[0024] According to the above-described aspects of the present invention, it is possible to suppress a decrease in the suction performance of the pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a cross-sectional view showing the overall structure of the vertical multistage pump according to the first embodiment.

[0026] Figure 2 It is a cross-sectional view showing the main structure of the vertical multistage pump according to the first embodiment.

[0027] Figure 3 This is a cross-sectional view showing the configuration of a main part of a vertical multi-stage pump according to a modified example of the first embodiment.

[0028] Figure 4 This is a cross-sectional view showing the configuration of a main part of a vertical multi-stage pump according to a modified example of the first embodiment.

[0029] Figure 5 This is a cross-sectional view showing the configuration of a main part of a vertical multi-stage pump according to a modified example of the first embodiment.

[0030] Figure 6 It is a cross-sectional view showing the main structure of a vertical multistage pump according to a second embodiment.

[0031] Figure 7 It is a cross-sectional view showing the main structure of a vertical multistage pump according to a third embodiment.

[0032] Figure 8 It is a cross-sectional view showing the main structure of a vertical multistage pump according to a fourth embodiment.

[0033] Figure 9 This is a plan view showing a guide portion included in a vertical multistage pump according to a fourth embodiment.

[0034] Figure 10 This is a cross-sectional view showing the configuration of a main part of a vertical multistage pump according to a modified example of the fourth embodiment.

[0035] Figure 11 It is a cross-sectional view showing the main structure of a vertical multistage pump according to a fifth embodiment.

[0036] Figure 12 It is a cross-sectional view showing the main structure of a vertical multistage pump according to a sixth embodiment.

[0037] Figure 13 This is a cross-sectional view showing the main structure of a vertical multi-stage pump according to a modified example of the sixth embodiment.

[0038] Figure 14It is a bottom view showing a cylindrical guide portion 70 included in a vertical multi-stage pump according to a modification of the sixth embodiment.

[0039] Figure 15 This is a cross-sectional view showing the main structure of a vertical multi-stage pump according to a modified example of the sixth embodiment.

[0040] Figure 16 It is a cross-sectional view showing the main structure of a vertical multistage pump according to a seventh embodiment. DETAILED DESCRIPTION

[0041] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0042] (First embodiment)

[0043] Figure 1 It is a cross-sectional view showing the overall structure of a vertical multistage pump 1 according to the first embodiment.

[0044] like Figure 1 As shown, a vertical multistage pump 1 includes a motor unit 10, a coupling unit 20, and a pump unit 30. The pump unit 30 includes a rotating shaft 2 extending in a vertical direction. In the following description, the direction in which the central axis O of the rotating shaft 2 extends (the vertical direction) is referred to as the axial direction, the direction orthogonal to the central axis O is referred to as the radial direction, and the direction surrounding the central axis O is referred to as the circumferential direction.

[0045] The motor unit 10 is arranged above the pump unit 30 and is connected to the rotating shaft 2 via the coupling 3. The motor unit 10 is supported on the pump unit 30 by the bracket 21 of the coupling unit 20. The motor unit 10 rotates at a specified rotational speed. It should be noted that the motor unit 10 does not have to rotate at a specified rotational speed, and is configured to achieve high and low speed rotation (speed change) even with commercial power supply by using an inverter or the like.

[0046] The coupling unit 20 includes a bracket 21 that surrounds the coupling 3 and a protective member 22 mounted on the bracket 21 and covering the coupling 3. The bracket 21 includes a base 21a to which the motor unit 10 is mounted, legs 21b that support the base 21a, and a cover 21c on which the legs 21b are erected. The base 21a is formed in an annular shape centered on the central axis O.

[0047] The legs 21b are connected to the lower surface of the base portion 21a at intervals along the circumferential direction. The coupling 3 is arranged between the legs 21b. The protective component 22 is installed on the legs 21b in a manner to block the space between the legs 21b. The cover portion 21c is connected to the lower end of the leg portion 21b and covers the upper part of the pump portion 30. The cover portion 21c is formed into a roughly cylindrical shape with the central axis O as the center, and an insertion hole 23 for the rotation shaft 2 to be inserted is formed in the center.

[0048] A mechanical seal 24 is disposed in the insertion hole 23. The mechanical seal 24 seals the gap between the rotating shaft 2 and the insertion hole 23, preventing fluid from leaking from the pump unit 30 through the insertion hole 23. A water inlet plug 21c1 and an exhaust plug 21c2 are disposed radially outward of the insertion hole 23 on the cover 21c. Multiple impellers 4 are fixed to the rotating shaft 2 and within the pump unit 30 at intervals in the axial direction.

[0049] The impeller 4 includes a main plate 5, side plates 6, and a plurality of blades 7. The main plate 5 is formed into a circular plate centered on the central axis O and is fixed to the rotating shaft 2. The side plates 6 are formed into an annular shape coaxial with the main plate 5 and are arranged with a gap therebetween. The main plate 5 and the side plates 6 are connected by the plurality of blades 7. The space enclosed by the main plate 5, side plates 6, and the plurality of blades 7 forms a flow path that guides the fluid in the radial direction. The side plates 6 form the suction port 8 of the impeller 4.

[0050] The pump unit 30 includes a cylindrical housing 31 that accommodates multiple impellers 4. The housing 31 internally forms a multi-stage pump chamber 30A, which is used to pressurize the fluid by the impellers 4. The housing 31 includes an intermediate housing 31a, an upper housing 31b disposed above the intermediate housing 31a, a lower housing 31c disposed below the intermediate housing 31a, and an outer housing 31d disposed outside the intermediate housing 31a and upper housing 31b.

[0051] The intermediate casing 31a is formed by stamping steel sheet or the like into a bottomed cylindrical shape. An opening is formed in the center of its bottom, through which the rotating shaft 2 is inserted. The intermediate casing 31a is stacked in multiple stages, corresponding to the number of impellers 4. A suction plate 33 is welded to the lower surface of the bottom of the intermediate casing 31a. Return vanes 34 are also welded to the lower surface of the suction plate 33. Furthermore, a backing ring 35 is attached to the inner wall of the bottom opening of the intermediate casing 31a to prevent fluid leakage around the suction port 8 of the impeller 4.

[0052] The upper housing 31b is formed in a bottomed cylindrical shape, similar to the intermediate housing 31a, and is stacked on the uppermost section of the intermediate housing 31a. Multiple communication holes 31b1 are formed in the peripheral wall of the upper housing 31b. The outer housing 31d is formed in a cylindrical shape, surrounding the radially outer sides of the intermediate housing 31a and the upper housing 31b. The outer housing 31d forms an annular flow path radially outward of the intermediate housing 31a and the upper housing 31b, communicating with the communication holes 31b1. The upper portions of the upper housing 31b and the outer housing 31d are covered by a housing cover 31e disposed on the lower surface of the lid 21c.

[0053] The lower housing 31c defines a communication space S1 that communicates with the suction port 8 at the lower end of the multi-stage pump chamber 30A, and also defines a communication space S2 (second communication space) that communicates with the annular flow path inside the outer housing 31d. The lower housing 31c includes a first frame 31c1 with the communication space S1 formed inside, and a second frame 31c2 that surrounds the outside of the first frame 31c1 and defines the communication space S2 between the first frame 31c1 and the second frame 31c2.

[0054] The first frame 31c1 is formed into a bottomed cylindrical shape (roughly disc-shaped) with a flange portion 31c4. The flange portion 31c4 is formed with a connecting hole 31c3. The connecting hole 31c3 axially penetrates the flange portion 31c4, connecting the annular flow path and the connecting space S2. The second frame 31c2 is formed into a bottomed cylindrical shape that accommodates the first frame 31c1 in a nested manner. By bringing the outer edge of the flange portion 31c4 of the first frame 31c1 into contact with the inner circumferential surface of the second frame 31c2, a gap (connecting space S2) is formed between the outer circumferential surface of the first frame 31c1 and the inner circumferential surface of the second frame 31c2.

[0055] The lower housing 31c includes a horizontally extending suction nozzle 36 and a similarly horizontally extending discharge nozzle 37. The suction nozzle 36 is joined to the peripheral wall of the second frame 31c2 and extends through the peripheral wall of the first frame 31c1 to the communication space S1. The discharge nozzle 37 is arranged back-to-back with the suction nozzle 36 on the same straight line. It is joined to the peripheral wall of the second frame 31c2 and does not penetrate the peripheral wall of the first frame 31c1, but communicates with the communication space S2.

[0056] A pump stage 32 is provided below the lower housing 31c. The pump stage 32 is axially connected to the bracket 21 of the coupling portion 20 via housing bolts 32a and nuts 32b. Multiple housing bolts 32a and nuts 32b are provided at intervals along the circumferential direction. Tightening these multiple housing bolts 32a and nuts 32b axially secures the multi-stage intermediate housing 31a, upper housing 31b, lower housing 31c, and housing cover 31e (specifically, the inner cylinder member 40, described later).

[0057] With the pump unit 30 configured as described above, as the impeller 4 rotates, fluid is drawn into the communication space S1 of the lower casing 31c through the suction nozzle 36. The fluid drawn into the communication space S1 of the lower casing 31c is then drawn into the first-stage impeller 4 through the suction port 8 at the lower end of the multi-stage pump chamber 30A, where its pressure is increased. The fluid discharged from the first-stage impeller 4 is directed to the suction side of the next-stage impeller 4 via the flow path formed by the return vanes 34 and the suction plate 33.

[0058] After being pressurized in multiple stages by the multiple impellers 4, the fluid flows into the upper casing 31b. The fluid flowing into the upper casing 31b descends through the annular flow path formed on the outer side of the upper casing 31b through the communication hole 31b1 and flows into the communication space S2 through the communication hole 31c3. The fluid flowing into the communication space S2 is discharged through the discharge nozzle 37 connected to the lower casing 31c. Since the discharge nozzle 37 is arranged on the same line as the suction nozzle 36, it can be installed midway in the piping of fluid equipment in factories, etc.

[0059] In such a vertical multistage pump 1, the fluid is sucked in horizontally from the suction nozzle 36, and in the communication space S1 of the lower casing 31c, the flow path changes by approximately 90 degrees toward the suction port 8 and flows into the impeller 4. When the flow path of the fluid changes in this way, a large number of swirling vortices are generated. Figure 2 The characteristic structure for suppressing the generation of such a swirling vortex will be described.

[0060] Figure 2 It is a cross-sectional view showing the main structure of a vertical multistage pump 1 according to the first embodiment.

[0061] like Figure 2 As shown, in vertical multistage pump 1, first suction port 8A of first-stage impeller 4A, located at the lower end of multistage pump chamber 30A, is larger than second suction port 8B of second-stage impellers 4B included in multistage pump chamber 30A. Specifically, diameter D1 of first suction port 8A is larger than diameter D2 of second suction port 8B.

[0062] The inlet diameter D4 (pump diameter) of the suction nozzle 36 is similarly determined based on the flow rate used, in accordance with JIS standards, etc. The diameter D2 of the second suction port 8B of the impeller 4B from the second stage onward is a standard suction port diameter determined by the inlet diameter D4 of the suction nozzle 36. Specifically, the diameter D2 of the second suction port 8B is 1 to 1.5 times the diameter of the inlet diameter D4 of the suction nozzle 36. Furthermore, the diameter D1 of the first suction port 8A is 1.5 to 2 times the diameter D2 of the second suction port 8B.

[0063] In addition, if Figure 2 As shown, the vertical multistage pump 1 includes an inner cylinder member 40 which is interposed between the multistage pump chamber 30A (intermediate housing 31a) and the lower housing 31c and expands the communication space S1 in the vertical direction.

[0064] Like the intermediate housing 31a, the inner cylindrical member 40 is formed by stamping steel sheet or the like into a bottomed cylindrical shape. The lowermost section of the intermediate housing 31a is stacked on the inner cylindrical member 40. The inner cylindrical member 40 has a lower opening 41 formed at the center of the bottom portion, centered on the central axis O. Furthermore, a recessed portion 42 (stepped portion) is formed radially outward of the lower opening 41 in the inner cylindrical member 40 to engage with the inner edge of the upper opening of the first frame 31c1 of the lower housing 31c.

[0065] The axial height H2 of the inner cylindrical member 40 is 0.5 to 2 times the height H1 of the intermediate casing 31a. If the height H2 of the inner cylindrical member 40 is the same as the height H1 of the intermediate casing 31a, components of the intermediate casing 31a (excluding the suction plate 33, return vanes 34, and backing ring 35) can be reused, allowing the inner cylindrical member 40 to be manufactured at a low cost. It should be noted that the cylindrical diameter D6 of the inner cylindrical member 40 (the inner diameter of the peripheral wall of the inner cylindrical member 40) can be the same as the cylindrical diameter of the intermediate casing 31a, taking into account lamination.

[0066] An annular wall 50 is attached by welding to the bottom lower surface of the inner cylindrical member 40, projecting inward from the peripheral wall of the inner cylindrical member 40. The annular wall 50 is formed in a doughnut shape, with an inner edge 51 formed around the central axis O. The inner diameter D3 of the annular wall 50 is 1.5 to 3 times the diameter of the standard suction port (the second suction port 8B of the impeller 4B) determined by the inlet diameter D4 of the suction nozzle 36.

[0067] According to the vertical multistage pump 1 constructed as described above, since it includes a rotating shaft 2 extending in the vertical direction, a plurality of impellers 4 fixed to the rotating shaft 2, a multistage pump chamber 30A accommodating the plurality of impellers 4 and having a first suction port 8A at the lower end thereof, a lower casing 31c including a suction nozzle 36 extending in the horizontal direction and forming a communication space S1 communicating between the suction nozzle 36 and the first suction port 8A, and an inner cylinder member 40 interposed between the multistage pump chamber 30A and the lower casing 31c and expanding the communication space S1 in the vertical direction, it is possible to suppress a decrease in the suction performance of the pump.

[0068] Specifically, the fluid flow from the suction nozzle 36 to the first suction port 8A of the impeller 4A generates turbulence, such as swirling vortices, due to a roughly 90-degree change from the horizontal to the vertical direction. However, after this 90-degree change, the inner cylinder member 40 expands the communication space S1 in the vertical direction, creating a distance. This turbulent flow is rectified to a certain extent before entering the first suction port 8A of the impeller 4A. Consequently, the swirling vortices entering the first suction port 8A of the impeller 4A are reduced, improving the pump's suction efficiency. Furthermore, by reducing the swirling vortices, wear and degradation of the pump's flow path can be suppressed, thereby increasing the pump's lifespan.

[0069] Furthermore, in this embodiment, the presence of the annular wall 50, which protrudes inwardly from the peripheral wall of the inner cylindrical member 40, allows the turbulent flow generated in the outer peripheral portion of the communication space S1 to be rectified. Consequently, the swirling vortex of the fluid flowing into the first suction port 8A of the impeller 4A is reduced, further improving the pump's suction efficiency.

[0070] Furthermore, according to the vertical multistage pump 1 having the above-described structure, since it includes the rotating shaft 2 extending in the vertical direction, the plurality of impellers 4 fixed to the rotating shaft 2, the multistage pump chamber 30A accommodating the plurality of impellers 4 and having a first suction port 8A at the lower end thereof for the first-stage impeller 4, and the lower casing 31c including a suction nozzle 36 extending in the horizontal direction and forming a communicating space S1 connecting the suction nozzle 36 and the first suction port 8A, the first suction port 8A is formed larger than the second suction port 8B of the impellers 4 from the second stage onwards provided in the multistage pump chamber 30A, thereby suppressing a decrease in the suction performance of the pump.

[0071] That is, the fluid flowing from the suction nozzle 36 into the connecting space S1 generates turbulence such as swirling vortices when entering the suction port 8 of the impeller 4 due to the narrowing of the flow path. However, since the diameter D1 of the first suction port 8A of the impeller 4A is larger than the diameter of the conventional standard suction port (the diameter D2 of the second suction port 8B), the change in the flow path diameter can be mitigated. As a result, the flow of the fluid can be made closer to a steady flow, and turbulence (swirling vortices, etc.) flowing into the first suction port 8A of the impeller 4A can be suppressed, thereby improving the suction efficiency of the pump. In addition, by reducing the swirling vortices, it is possible to suppress wear and degradation of the flow path portion of the pump, thereby increasing the life of the pump.

[0072] In the first embodiment described above, the following Figures 3 to 5 The modified example shown.

[0073] Figure 3 This is a cross-sectional view showing the configuration of a main part of a vertical multistage pump 1 according to a modified example of the first embodiment.

[0074] exist Figure 3 In the vertical multistage pump 1 shown, the first suction port 8A of the first-stage impeller 4A, located at the lower end of the multistage pump chamber 30A, is not larger than the second suction port 8B of the second-stage impellers 4B included in the multistage pump chamber 30A. In other words, the diameter D1 of the first suction port 8A can be equal to the diameter D2 (standard suction port diameter) of the second suction port 8B. Even with this configuration, the inclusion of the inner cylinder member 40 allows the communication space S1 to be expanded vertically, rectifying the fluid flow and suppressing a decrease in the pump's suction performance.

[0075] Figure 4 This is a cross-sectional view showing the configuration of a main part of a vertical multistage pump 1 according to a modified example of the first embodiment.

[0076] exist Figure 4 In the illustrated vertical multistage pump 1, the center O1 of the inner edge 51 of the annular wall 50 is eccentric relative to the center (central axis O) of the suction port 8 of the impeller 4. As an example, the horizontal eccentricity G1 of the inner edge 51 of the annular wall 50 relative to the central axis O can be 0.1 mm to 40 mm. It should be noted that the planar shape of the inner edge 51 of the annular wall 50, as viewed from the axial direction, is not limited to a circle and may also be an ellipse.

[0077] This configuration prevents the center O1 of the annular wall 50 from being aligned with the center (central axis O) of the impeller 4's suction port 8. This prevents the uniform flow of the swirling vortex generated when the fluid flows from the suction nozzle 36 into the lower casing 31c and then changes its flow path by approximately 90 degrees (disturbing the flow) into the inner cylinder member 40, thereby reducing the swirling vortex. By reducing this swirling vortex, fluid loss is suppressed, resulting in improved pump suction performance compared to conventional structures.

[0078] Figure 5 This is a cross-sectional view showing the configuration of a main part of a vertical multistage pump 1 according to a modified example of the first embodiment.

[0079] exist Figure 5 In the vertical multistage pump 1 shown, the inner cylinder member 40 is not interposed between the multistage pump chamber 30A (intermediate casing 31a) and the lower casing 31c. In other words, the intermediate casing 31a can be directly laminated onto the lower casing 31c. Even with this configuration, by making the first suction port 8A of the first-stage impeller 4A, located at the lower end of the multistage pump chamber 30A, larger than the second suction port 8B of the second-stage and subsequent impellers 4B in the multistage pump chamber 30A, swirling vortices can be reduced, thus suppressing a decrease in the pump's suction performance.

[0080] (Second embodiment)

[0081] Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above embodiment will be denoted by the same reference numerals, and their description will be simplified or omitted.

[0082] Figure 6 It is a cross-sectional view showing the main structure of a vertical multistage pump 1 according to the second embodiment.

[0083] like Figure 6 As shown, the vertical multistage pump 1 of the second embodiment differs from the above-described embodiment in that it includes a rotation preventing plate 60 extending radially toward the central axis O of the rotating shaft 2 in the communication space S1 .

[0084] like Figure 6As shown, the anti-rotation plate 60 is formed into a rectangular plate shape and is positioned on the opposite side of the suction nozzle 36 in the communication space S1. The anti-rotation plate 60 is joined to the bottom upper surface and the inner surface of the peripheral wall of the first frame 31c1 of the lower housing 31c and extends radially from the peripheral wall of the first frame 31c1 to the central axis O. Furthermore, the anti-rotation plate 60 extends vertically from the bottom upper surface of the first frame 31c1 to a position above an extension line L1 extending through the center of the suction nozzle 36. As an example, the anti-rotation plate 60 has a thickness of 3 mm and dimensions of 70 mm x 75 mm.

[0085] With this configuration, the anti-swirl plate 60 can be used to divide and straighten the swirling vortex generated when the fluid flows from the suction nozzle 36 into the lower housing 31c and then changes its flow path by 90 degrees. This straightening of the swirling vortex reduces fluid loss, improving the pump's suction performance compared to conventional structures. Furthermore, by reducing the swirling vortex, wear and degradation of the pump's flow path can be suppressed, thereby extending the pump's lifespan.

[0086] Therefore, according to the vertical multistage pump 1 of the second embodiment described above, a decrease in the suction performance of the pump can be suppressed by adopting a configuration including a rotating shaft 2 extending in the vertical direction, a plurality of impellers 4 fixed to the rotating shaft 2, a multistage pump chamber 30A accommodating the plurality of impellers 4 and having a suction port 8 for the first-stage impeller 4 at its lower end, a lower casing 31c including a suction nozzle 36 extending in the horizontal direction and forming a communication space S1 that communicates between the suction nozzle 36 and the suction port 8, and a rotation preventing plate 60 extending radially toward the central axis O of the rotating shaft 2 in the communication space S1.

[0087] (Third embodiment)

[0088] Next, a third embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above embodiment will be denoted by the same reference numerals, and their description will be simplified or omitted.

[0089] Figure 7 It is a cross-sectional view showing the main structure of a vertical multistage pump 1 according to a third embodiment.

[0090] like Figure 7 As shown, the vertical multistage pump 1 of the third embodiment differs from the above-described embodiments in that it includes a raised portion 61 raised in a conical shape centered on the rotary shaft 2 on the bottom surface of the communication space S1.

[0091] like Figure 7As shown, the raised portion 61 is formed into a cone shape coaxial with the central axis O, and rises from the bottom surface of the connecting space S1 toward the vertical direction. The raised portion 61 can be formed by stamping the bottom of the first frame 31c1 of the lower shell 31c into a cone shape. It should be noted that the raised portion 61 can also be formed by joining a conical plate to the bottom upper surface of the first frame 31c1. The raised portion 61 extends from the bottom upper surface of the first frame 31c1 toward the vertical direction at a height below the extension line L1 passing through the center of the suction nozzle 36. As an example, the raised portion 61 has The size of the front end has R20 rounded corners.

[0092] With this configuration, when fluid flows from the suction nozzle 36 into the lower housing 31c and then changes its flow path 90 degrees, it flows along the conical protrusion 61, thereby suppressing the generation of vortexes. By suppressing vortexes, fluid loss is reduced, improving the pump's suction performance compared to conventional structures. Furthermore, by reducing vortexes, wear and degradation of the pump's flow path are suppressed, thereby extending the pump's lifespan.

[0093] Therefore, according to the vertical multistage pump 1 of the third embodiment described above, a decrease in the suction performance of the pump can be suppressed by adopting a configuration including a rotating shaft 2 extending in the vertical direction, a plurality of impellers 4 fixed to the rotating shaft 2, a multistage pump chamber 30A accommodating the plurality of impellers 4 and having a suction port 8 for the first-stage impeller 4 at its lower end, a lower casing 31c including a suction nozzle 36 extending in the horizontal direction and forming a communication space S1 that communicates between the suction nozzle 36 and the suction port 8, and a raised portion 61 raised in a conical shape centered on the rotating shaft 2 on the bottom surface of the communication space S1.

[0094] (Fourth embodiment)

[0095] Next, a fourth embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and their description will be simplified or omitted.

[0096] Figure 8 It is a cross-sectional view showing the main structure of a vertical multistage pump 1 according to a fourth embodiment. Figure 9 It is a plan view showing the guide portion 62 included in the vertical multistage pump 1 according to the fourth embodiment.

[0097] like Figure 8 As shown, the vertical multistage pump 1 of the fourth embodiment differs from the above-described embodiments in that it includes a guide portion 62 that is arranged on an extension line L1 of the suction nozzle 36 in the communication space S1 and that bends from the horizontal direction toward the vertically upward direction.

[0098] like Figure 8As shown, the guide portion 62 includes a horizontal portion 62a extending horizontally from below the suction nozzle 36 in the communication space S1, and a curved portion 62b curved vertically upward from the horizontal portion 62a. The horizontal portion 62a extends radially from below the suction nozzle 36 to the central axis O. The curved portion 62b extends radially outward from the front end (central axis O) of the horizontal portion 62a relative to the opening edge of the suction port 8 of the impeller 4 on the opposite side of the suction nozzle 36.

[0099] like Figure 9 As shown, the guide portion 62 has a tongue shape with a rounded front end when viewed from above. The portion of the tongue shape with a constant width is the above-mentioned horizontal portion 62a. In addition, the portion of the tongue shape that is semicircular is the above-mentioned curved portion 62b. Portions other than the outer peripheral edge 62c of the guide portion 62 can also be recessed to form a disc shape and a spoon shape. In this way, the fluid that collides with the guide portion 52 can be concentrated toward the suction port 8 of the impeller 4. As an example, for the inlet diameter D4 of the suction nozzle 36 (pump diameter: 32mm), the guide portion 62 has a size of 84mm×33mm and a height of 70mm when viewed from above.

[0100] According to the above structure, the flow from the suction nozzle 36 to the suction port 8 of the impeller 4 generates turbulence due to the change of approximately 90 degrees from the horizontal direction to the vertical direction. Figure 8 As shown, since the guide portion 62 is arranged on the extension line L1 of the suction nozzle 36, the angle change of the fluid becomes gentle, which can reduce the generation of turbulence. By suppressing such turbulence flowing into the suction port 8 of the impeller 4, the suction efficiency is improved. In addition, the shape of the guide portion 62 is designed to optimize the size to achieve the above-mentioned effect, which can minimize the generation of turbulence and improve the suction efficiency of the pump.

[0101] Therefore, according to the vertical multistage pump 1 of the fourth embodiment described above, a decrease in the suction performance of the pump can be suppressed by adopting a configuration including a rotating shaft 2 extending in the vertical direction, a plurality of impellers 4 fixed to the rotating shaft 2, a multistage pump chamber 30A accommodating the plurality of impellers 4 and having a suction port 8 for the first-stage impeller 4 at the lower end, a lower casing 31c including a suction nozzle 36 extending in the horizontal direction and forming a communication space S1 for communicating between the suction nozzle 36 and the suction port 8, and a guide portion 62 arranged in the communication space S1 on an extension line L1 of the suction nozzle 36 and curved from the horizontal direction toward the vertically upward direction.

[0102] In the fourth embodiment described above, the following Figure 10 The modified example shown.

[0103] Figure 10 This is a cross-sectional view showing the configuration of a main part of a vertical multistage pump 1 according to a modified example of the fourth embodiment.

[0104] exist Figure 10 In the vertical multistage pump 1 shown, the guide portion 62 is not joined to the first frame 31c1 of the lower housing 31c, but is formed integrally with the bottom of the first frame 31c1 by stamping. This configuration allows the first frame 31c1 and the guide portion 62 to be formed from a single component, thereby reducing the number of parts and improving assembly efficiency.

[0105] (Fifth embodiment)

[0106] Next, a fifth embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and their description will be simplified or omitted.

[0107] Figure 11 It is a cross-sectional view showing the main structure of a vertical multistage pump 1 according to a fifth embodiment.

[0108] like Figure 11 As shown, the vertical multi-stage pump 1 of the fifth embodiment is different from the above-mentioned embodiments in that the diameter of the suction nozzle 36 is enlarged.

[0109] like Figure 11 As shown, the inlet diameter D4 of the suction nozzle 36 is larger than the inlet diameter D4 of the suction nozzle 36 in the above-mentioned embodiment (the standard inlet diameter). As an example, the inlet diameter D4 of the suction nozzle 36 is 1 to 1.2 times the standard inlet diameter D4. The outlet diameter D5 of the suction nozzle 36 is 1.1 to 1.3 times the inlet diameter D4 of the suction nozzle 36.

[0110] The above configuration reduces fluid loss when the fluid flows from the suction nozzle 36 into the lower housing 31c by increasing the diameter of the suction nozzle 36, and also reduces the generation of swirling vortices. By suppressing swirling vortices, fluid loss is reduced, improving the pump's suction performance compared to conventional configurations. Furthermore, by reducing swirling vortices, wear and degradation of the pump's flow path are suppressed, thereby extending the pump's lifespan.

[0111] Therefore, according to the vertical multistage pump 1 of the fifth embodiment described above, a deterioration in the pump's suction performance can be suppressed by adopting a configuration including a rotating shaft 2 extending in the vertical direction, a plurality of impellers 4 fixed to the rotating shaft 2, a multistage pump chamber 30A accommodating the plurality of impellers 4 and having a suction port 8 for the first-stage impeller 4 at its lower end, a lower casing 31c including a suction nozzle 36 extending in the horizontal direction and forming a communicating space S1 communicating between the suction nozzle 36 and the suction port 8, and a configuration in which the outlet diameter D5 of the suction nozzle 36 is enlarged compared to the inlet diameter D4 of the suction nozzle 36.

[0112] (Sixth embodiment)

[0113] Next, a sixth embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and their description will be simplified or omitted.

[0114] Figure 12 It is a cross-sectional view showing the main structure of a vertical multistage pump 1 according to a sixth embodiment.

[0115] like Figure 12 As shown, the vertical multistage pump 1 of the sixth embodiment differs from the above-mentioned embodiments in that it includes a cylindrical guide portion 70 extending vertically from the lower end opening 41 of the inner cylinder member 40 to the suction port 8 .

[0116] like Figure 12 As shown, the cylindrical guide portion 70 is formed into a cylindrical shape coaxial with the central axis O, and the outer periphery of its lower end is engaged with the lower end opening 41 of the inner cylindrical member 40 (and the inner end edge 51 of the annular wall 50). The upper end of the cylindrical guide portion 70 extends to the same height as the suction port 8 of the impeller 4 and surrounds the suction port 8. The inner diameter of the cylindrical guide portion 70 is approximately the same as the inner diameter D3 of the annular wall 50. In other words, the inner diameter of the cylindrical guide portion 70 is 1.5 to 3 times the diameter of the standard suction port (the suction port 8 of the impeller 4) determined based on the inlet diameter D4 of the suction nozzle 36.

[0117] According to the above configuration, the provision of cylindrical guide 70 creates an inner wall surface of the fluid flow path that is smoother than the circumferential wall of inner cylindrical member 40. This straightens the swirling vortex generated when the fluid flows from suction nozzle 36 into lower housing 31c and then undergoes a 90-degree change in flow path. This straightening of the swirling vortex reduces fluid loss, improving the pump's suction performance compared to conventional structures. Furthermore, by reducing the swirling vortex, wear and degradation of the pump's flow path are suppressed, thereby extending the pump's lifespan.

[0118] Therefore, according to the vertical multistage pump 1 of the sixth embodiment described above, a decrease in the suction performance of the pump can be suppressed by adopting a configuration including a rotating shaft 2 extending in the vertical direction, a plurality of impellers 4 fixed to the rotating shaft 2, a multistage pump chamber 30A that accommodates the plurality of impellers 4 and has a suction port 8 at the lower end for the first-stage impeller 4, a lower casing 31c that has a suction nozzle 36 extending in the horizontal direction and forms a communication space S1 that communicates between the suction nozzle 36 and the suction port 8, an inner cylinder member 40 that is sandwiched between the multistage pump chamber 30A and the lower casing 31c and expands the communication space S1 in the vertical direction, and a cylindrical guide portion 70 that extends in the vertical direction from the lower end opening 41 of the inner cylinder member 40 to the suction port 8.

[0119] In the sixth embodiment described above, the following Figures 13 to 15 The modified example shown.

[0120] Figure 13 This is a cross-sectional view showing the configuration of a main part of a vertical multistage pump 1 according to a modified example of the sixth embodiment. Figure 14 It is a bottom view of a cylindrical guide portion 70 included in a vertical multistage pump 1 according to a modified example of the sixth embodiment.

[0121] Figure 13 and Figure 14 The illustrated vertical multi-stage pump 1 has a rectifying grid 80 provided inside the cylinder guide 70 .

[0122] like Figure 13 As shown, the rectifier grid 80 is mounted on the lower end opening of the cylindrical guide portion 70. It should be noted that the rectifier grid 80 can also be integrally formed by stamping (bottom punching) the cylindrical guide portion 70 (cylindrical with a bottom). Figure 14 As shown, the flow rectifying grid 80 is formed with a plurality of grids, which extend horizontally in the front, back, left, and right directions, and allows the fluid to flow into the lower end opening of the cylindrical guide portion 70. According to this structure, the rectifying effect of the cylindrical guide portion 70 can be further improved.

[0123] Figure 15 This is a cross-sectional view showing the configuration of a main part of a vertical multistage pump 1 according to a modified example of the sixth embodiment.

[0124] exist Figure 15 In the vertical multistage pump 1 shown, the center O1 of the cylindrical guide portion 70 is eccentric relative to the center (central axis O) of the suction port 8 of the impeller 4. As an example, the horizontal eccentricity G2 of the center O1 of the cylindrical guide portion 70 relative to the central axis O can be 0.1 mm to 40 mm.

[0125] According to this structure, by misaligning the center O1 of the cylindrical guide portion 70 with the center (central axis O) of the suction port 8 of the impeller 4, the swirling vortex generated when the fluid flows from the suction nozzle 36 into the lower casing 31c and then changes its flow path by approximately 90 degrees can be blocked from uniformly flowing into the cylindrical guide portion 70 (disturbing the flow), thereby reducing the swirling vortex. By reducing this swirling vortex, fluid loss can be suppressed, and the suction performance of the pump can be improved compared to conventional structures.

[0126] (Seventh embodiment)

[0127] Next, a seventh embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and their description will be simplified or omitted.

[0128] Figure 16 It is a cross-sectional view showing the main structure of a vertical multistage pump 1 according to a seventh embodiment.

[0129] like Figure 16 As shown, the vertical multi-stage pump 1 of the seventh embodiment differs from the above-mentioned embodiment in that it has a first anti-rotation plate 60 (the above-mentioned anti-rotation plate 60) extending radially toward the center axis O of the rotating shaft 2 in the communicating space S1 of the lower casing 31c, and a second anti-rotation plate 90 extending radially toward the center axis O of the rotating shaft 2 on the inner side of the inner cylinder member 40.

[0130] like Figure 16 As shown, the first anti-rotation plate 60 and the second anti-rotation plate 90 are each formed into a rectangular plate shape. The first anti-rotation plate 60 is positioned opposite the suction nozzle 36 in the communication space S1 of the lower housing 31c. The second anti-rotation plate 90 is positioned on the inner side of the inner cylinder member 40, closer to the suction nozzle 36. In other words, the first anti-rotation plate 60 and the second anti-rotation plate 90 are positioned in a point-symmetrical relationship about the central axis O when viewed from above.

[0131] According to the above structure, the first anti-rotation plate 60 and the second anti-rotation plate 90 can be used to rectify the vortex generated when the fluid flows from the suction nozzle 36 into the lower housing 31c and then changes its flow path by 90 degrees, dividing it into two stages and directing it in opposite directions. This rectification of the vortex can suppress fluid loss, improving the pump's suction performance compared to conventional structures. In addition, by reducing the vortex, wear and degradation of the pump's flow path can be suppressed, thereby increasing the pump's lifespan.

[0132] Therefore, according to the vertical multistage pump 1 of the seventh embodiment described above, a deterioration in the suction performance of the pump is suppressed by adopting a configuration including a rotating shaft 2 extending in the vertical direction, a plurality of impellers 4 fixed to the rotating shaft 2, a multistage pump chamber 30A accommodating the plurality of impellers 4 and having a suction port 8 at the lower end thereof for the first-stage impeller 4, a lower casing 31c including a suction nozzle 36 extending in the horizontal direction and forming a communication space S1 for communicating between the suction nozzle 36 and the suction port 8, an inner cylinder member 40 interposed between the multistage pump chamber 30A and the lower casing 31c and expanding the communication space S1 in the vertical direction, a first anti-rotation plate 60 extending radially toward the central axis O of the rotating shaft 2 in the communication space S1 of the lower casing 31c, and a second anti-rotation plate 90 extending radially toward the central axis O of the rotating shaft 2 on the inner side of the inner cylinder member 40.

[0133] While the preferred embodiments of the present invention have been described above, it should be understood that these are merely illustrative of the present invention and should not be construed as limiting the present invention. Additions, omissions, substitutions, and other modifications may be made without departing from the scope of the present invention. Therefore, the present invention is subject to the appended claims and should not be construed as being limited by the foregoing description.

[0134] For example, the present invention can be applied not only to the above-mentioned vertical multistage pump 1 (a vertical multistage in-line pump in which the suction nozzle 36 and the discharge nozzle 37 are arranged in a straight line), but also to a vertical multistage pump (such as a vertical multistage immersion pump) in which the positional relationship between the suction nozzle 36, the communicating space S1 and the suction port 8 is the same.

[0135] Furthermore, for example, the above-described embodiments and modifications can be combined and replaced as appropriate.

[0136] Industrial applicability

[0137] The present invention relates to a vertical multi-stage pump capable of suppressing the reduction of the suction performance of the pump.

[0138] Description of Reference Numerals

[0139] 1 Vertical multistage pump

[0140] 2 rotation axes

[0141] 4 impellers

[0142] 8 suction port

[0143] 8A No. 1 suction port

[0144] 8B Second suction port

[0145] 30A multistage pump room

[0146] 31c lower housing

[0147] 36 suction nozzle

[0148] 40 Inner cylinder parts

[0149] 41 bottom opening

[0150] 50 Annular wall

[0151] 51 inner edge

[0152] 60 anti-rotation plate (first anti-rotation plate)

[0153] 61 bulge

[0154] 62 Guidance Department

[0155] 70 Cylinder guide

[0156] 80 rectifier grid

[0157] 90 2nd anti-rotation plate

[0158] D4 inlet diameter

[0159] D5 outlet diameter

[0160] L1 extension cable

[0161] S1 Connected Space

Claims

1. A vertical multistage pump, characterized in that: have: a rotation axis extending in a vertical direction; a plurality of impellers fixed to the rotating shaft; a multi-stage pump chamber accommodating a plurality of the impellers and having a suction port for a first-stage impeller at a lower end; a lower housing having a suction nozzle extending in a horizontal direction and forming a communication space for communicating the suction nozzle with the suction port; an inner cylinder member, which is sandwiched between the multi-stage pump chamber and the lower housing and expands the communication space in the vertical direction; as well as an annular wall provided on the bottom lower surface of the inner cylinder member and protruding toward the inner side of the inner cylinder member more than the peripheral wall of the inner cylinder member; A space serving as a portion of the communication space is formed by the lower end surface of the multi-stage pump chamber near the suction port, the peripheral wall of the inner cylinder member, and the annular wall.

2. The vertical multistage pump according to claim 1, characterized in that: The center of the inner edge of the annular wall is eccentric with respect to the center of the suction port.

3. The vertical multistage pump according to claim 1 or 2, characterized in that: A cylindrical guide portion is provided, which extends vertically from the lower end opening of the inner cylindrical member to the suction port.

4. The vertical multistage pump according to claim 3, characterized in that: A rectifying grid is provided on the inner side of the cylindrical guide portion.

5. The vertical multi-stage pump according to claim 3, characterized in that: have: a first anti-rotation plate extending radially toward the central axis of the rotating shaft in the communicating space of the lower housing; and The second anti-rotation plate extends radially toward the central axis of the rotating shaft on the inner side of the inner cylinder member.

6. The vertical multi-stage pump according to claim 1, characterized in that: have: a rotation axis extending in a vertical direction; a plurality of impellers fixed to the rotating shaft; a multi-stage pump chamber accommodating the plurality of impellers and having a first suction port of a first-stage impeller at a lower end; and The lower housing includes a suction nozzle extending in the horizontal direction, forming a communication space for communicating the suction nozzle with the first suction port. The first suction port is formed to be larger than the second suction port of the impellers from the second stage onwards.

7. The vertical multi-stage pump according to claim 6, characterized in that: A rotation preventing plate is provided, which extends radially toward the central axis of the rotating shaft in the communicating space.

8. The vertical multi-stage pump according to claim 6 or 7, characterized in that: A raised portion is provided on the bottom surface of the communication space and is raised in a conical shape with the rotation axis as the center.

9. The vertical multistage pump according to claim 6 or 7, characterized in that: A guide portion is provided, which is arranged on an extension line of the suction nozzle in the communication space and is bent from a horizontal direction toward a vertically upward direction.

10. The vertical multi-stage pump according to claim 6 or 7, characterized in that: The outlet diameter of the suction nozzle is larger than the inlet diameter of the suction nozzle.

11. A vertical multistage pump, characterized in that: have: a rotation axis extending in a vertical direction; a plurality of impellers fixed to the rotating shaft; a multi-stage pump chamber accommodating a plurality of the impellers and having a suction port for a first-stage impeller at a lower end; a lower housing having a suction nozzle extending in a horizontal direction and forming a communication space for communicating the suction nozzle with the suction port; an inner cylinder member, which is sandwiched between the multi-stage pump chamber and the lower housing and expands the communication space in the vertical direction; as well as an annular wall that protrudes toward the inner side of the inner cylinder member relative to the peripheral wall of the inner cylinder member, The center of the inner edge of the annular wall is eccentric with respect to the center of the suction port.

Images