Pumping device

Abstract

To provide a pump device that can share a casing.SOLUTION: A pump device 1 comprises: a rotating shaft 12; an impeller 22 provided on the rotating shaft 12; a suction casing 31 housing the impeller 22; a discharge casing 32 provided on a secondary side of the impeller 22, forming a flow passage with the suction casing, and comprising a discharge port 32c; and a return casing 33 comprising a first return blade 33d provided between the secondary side of the impeller 22 and the discharge casing 32, and a supported part formed so as to be capable of being sandwiched between the suction casing 31 and the discharge casing 32, and held in the flow passage.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pump device for pressure-feeding liquid.

Background Art

[0002] Conventionally, as centrifugal pumps, single-stage pump devices having a single impeller and multi-stage pump devices having a plurality of impellers are known (see, for example, Patent Document 1 to Patent Document 3). In such pump devices, if the number of impellers is configured differently, the casing also needs to have a different shape in order to satisfy the water pumping performance.

Prior Art Literature

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described pump device, since the casing needs to have a different shape according to the number of impellers, there is a problem that the number of types of components increases, leading to an increase in manufacturing cost and management cost. For this reason, it is required to satisfy the water pumping performance and to share components.

[0005] Accordingly, an object of the present invention is to provide a pump device that allows components constituting the casing to be shared even when the number of impellers is different.

Means for Solving the Problems

[0006] According to one aspect of the present invention, a pump device comprises a rotating shaft, an impeller provided on the rotating shaft, a suction casing housing the impeller, a discharge casing provided on the secondary side of the impeller and having a discharge port in the radial direction of the rotating shaft, and a return casing having a first return vane provided between the secondary side of the impeller and the discharge casing, and formed to be sandwiched between the suction casing and the discharge casing. The impeller is provided in multiple locations, and is further provided with an intermediate casing that houses the impeller and has a second return blade that guides water from the primary side impeller to the housed impeller, which is provided between the suction casing and the return casing and is formed so that the return casing can be sandwiched between the discharge casings, and the minimum inner diameter of the first return blade is larger than the minimum inner diameter of the second return blade. . [Effects of the Invention]

[0007] According to the present invention, a highly efficient pump device can be provided that allows for the sharing of casings. [Brief explanation of the drawing]

[0008] [Figure 1] A side view showing a partial cross-section of a single-stage pump, illustrating the configuration of a pump device according to one embodiment of the present invention. [Figure 2] A side view showing a partial cross-section of a multi-stage pump, illustrating the configuration of a pump device according to one embodiment of the present invention. [Figure 3] This cross-sectional view shows a schematic diagram of the casing structure used in the pump device, disassembled for easy viewing. [Figure 4] A cross-sectional view showing the configuration of the discharge casing of the same casing. [Figure 5] A bottom view showing the configuration of the discharge casing. [Figure 6] A cross-sectional view showing the configuration of the return casing of the same casing. [Figure 7] A top view showing the configuration of the return casing. [Figure 8] A bottom view showing the configuration of the return casing, with some parts omitted. [Modes for carrying out the invention]

[0009] The configuration of the pump device 1 according to an embodiment of the present invention will be described below with reference to Figures 1 to 8. Figure 1 is a side view showing a configuration of a pump device 1 according to one embodiment of the present invention, specifically an example of a single-stage pump, with a partial cross-section. Figure 2 is a side view showing a configuration of a pump device 1, specifically an example of a multi-stage pump, with a partial cross-section. Figure 3 is a cross-sectional view showing an exploded schematic of the configuration of the casing 21 used in the pump device 1. Figure 4 is a cross-sectional view showing the configuration of the discharge casing 32 of the casing 21, and Figure 5 is a bottom view showing the configuration of the discharge casing 32. Figure 6 is a cross-sectional view showing the configuration of the return casing 33 of the casing 21, Figure 7 is a top view showing the configuration of the return casing 33, and Figure 8 is a bottom view showing the configuration of the return casing 33 with some parts omitted.

[0010] As shown in Figures 1 and 2, the pump device 1 is a centrifugal pump, and is either a single-stage pump having one impeller 22 or a multi-stage pump having multiple impellers 22. Furthermore, the pump device 1 is, for example, a vertical pump used with the rotating shaft 12 aligned in the vertical direction (direction of gravity), but it may also be a horizontal pump used with the rotating shaft 12 aligned in the horizontal direction. As a specific example, as shown in Figures 1 and 2, the pump device 1 comprises a motor 11, a rotating shaft 12, and a pump 13.

[0011] The motor 11 is fixed to the pump 13. The motor 11 drives the pump 13 by rotating the rotating shaft 12. The motor 11 includes, for example, a motor casing 11a, a stator provided inside the motor casing 11a, a rotor that rotates relative to the stator, and a motor shaft 11b fixed to the rotor. The motor 11 also has, for example, a cooling fan that rotates due to the rotation of the motor shaft 11b.

[0012] The rotating shaft 12 rotates the impeller 22 of the pump 13 (described later) by the rotation of the rotor of the motor 11. The rotating shaft 12 comprises, for example, a motor shaft 11b and a pump shaft 12a, and is formed by integrally connecting the motor shaft 11b and the pump shaft 12a with a shaft coupling 12b. For example, the pump shaft 12a of the rotating shaft 12 is formed so that the impeller 22 can be fixed to it. Alternatively, the rotating shaft 12 may not have a pump shaft 12a, and the motor shaft 11b may extend into the casing 21 of the pump 13 (described later), with the impeller 22 directly fixed to the motor shaft 11b.

[0013] The pump 13 comprises a casing 21, one or more impellers 22, and a shaft sealing member 23. The pump 13 includes a pump shaft 12a, and the rotation of the pump shaft 12a rotates the impellers 22, thereby pressurizing the liquid within the casing 21 from the primary side to the secondary side. The pump 13 is a centrifugal pump formed by a casing 21 that does not have a volute shape.

[0014] As shown in Figures 1 and 2, the casing 21 comprises a suction casing 31, a discharge casing 32, a return casing 33, and a packing 35. The casing 21 forms a flow path through which liquid, which is sucked into the impeller 22 and pressurized by the impeller 22, flows by connecting the suction casing 31, the return casing 33, and the discharge casing 32. Specifically, in the casing 21, the suction casing 31 and the discharge casing 32 form a flow path, and the return casing 33 is held in this flow path by being sandwiched between the suction casing 31 and the discharge casing 32.

[0015] Further, when the pump device 1 is a multi-stage pump, as shown in Figure 2, the casing 21 further includes intermediate casings 34 the number of which is one less than the number of the impellers 22. For example, as shown in Figure 1, the casing 21 is integrally formed by sandwiching the return casing 33 inside the casing 21 with the suction casing 31 and the discharge casing 32, or as shown in Figure 2, sandwiching the return casing 33 inside the casing 21 with the discharge casing 32 and the intermediate casing 34, and fixing the suction casing 31 and the discharge casing 32 with fastening members 90 such as bolts and nuts. Note that the return casing 33 and / or the intermediate casing 34 may be configured to be fixed to the suction casing 31 and / or the discharge casing 32 by the fastening members 90.

[0016] Further, as shown in Figure 2 and Figure 3, when the casing 21 is configured to have the intermediate casings 34, the suction casing 31 is disposed at the most primary side in the liquid flow direction, then one or a plurality of the intermediate casings 34 are disposed, the return casing 33 is disposed on the secondary side of the intermediate casings 34, and the discharge casing 32 is disposed on the secondary side of the return casing 33.

[0017] The suction casing 31 is formed so as to be capable of accommodating the impeller 22. The suction casing 31 is formed so that one of the return casing 33 and the intermediate casing 34 can be disposed on the motor 11 side. As shown in Figure 3, the suction casing 31 includes, for example, a barrel portion 31a, a suction port 31c having a first flange 31b, a second flange 31e in which bolt holes 31d are formed, and a support portion 31f.

[0018] The body portion 31a houses the impeller 22 and also houses a part of the return casing 33 or the intermediate casing 34. One end of the body portion 31a is open, and the other end of the body portion 32a is provided with a suction port 31c. The body portion 31a has an end face 31a1 formed at one end that abuts against one of the discharge casing 32 and the intermediate casing 34, and a seal groove 31a2 formed on the end face 31a1. The end face 31a1 is formed in a planar shape with an annular shape perpendicular to the axial direction. The seal groove 31a2 is, for example, an annular groove with a rectangular cross-section formed on the inner periphery of the end face 31a1.

[0019] The suction port 31c is connected, for example, to a pipe via the first flange 31b, and is supplied with a liquid such as water that is pressurized by the pump 13. The second flange 31e is formed on the outer circumferential surface of one open end of the body portion 31a.

[0020] Multiple bolt holes 31d are formed in the second flange 31e, in which fastening members 90 are placed. The second flange 31e is, for example, provided with multiple plate-shaped projections in which bolt holes 31d are formed, or is an annular or arc-shaped plate-shaped projection in which multiple bolt holes 31d are formed.

[0021] The support portion 31f is formed to support the return casing 33 and the intermediate casing 34. The support portion 31f is formed, for example, by an end face formed on the other end side of the body portion 31a, beyond the end face of the opening end of the body portion 31a. That is, the support portion 31f is formed by a recessed surface from the end face of one end of the body portion 31a.

[0022] As shown in Figures 4 and 5, the discharge casing 32 includes, for example, a body portion 32a, a discharge port 32c having a third flange 32b, a mounting portion 32d, a fourth flange 32f having bolt holes 32e, a support portion 32g, and a fixing portion 32h.

[0023] The body portion 32a has an open end, forming a space on the secondary side of the return casing 33 in the direction of liquid flow. The pump shaft 12a and shaft seal member 23 are positioned in the center of the space formed on the secondary side of the return casing 33. A discharge port 32c is provided on a part of the outer circumference of the body portion 32a in the circumferential direction. The body portion 32a is formed in a dome shape, and the dome-shaped internal space is recessed in a cylindrical shape at the center by the mounting portion 32d. The internal space of the body portion 32a faces the return casing 33 in the axial direction. The body portion 32a has an end face 32a1 formed at one end that abuts against the suction casing 31. The end face 32a1 is formed so as to be able to abut against the end face 31a1 of the body portion 31a of the suction casing 31, and so as to be able to face the seal groove 31a2 of the body portion 31a of the suction casing 31. Furthermore, if the pump device 1 is a multi-stage pump and has an intermediate casing 34, the end face 32a1 is formed so as to be able to abut against the end face 34a1 of the body portion 34a of the intermediate casing 34 (described later), and so as to be able to face the seal groove 34a2 of the body portion 34a of the intermediate casing 34 (described later).

[0024] The discharge port 32c is connected to piping, for example, via a third flange 32b, and discharges the pressurized liquid from the pump 13 to the secondary side. In the axial direction, the end of the discharge port 32c that is continuous with the internal space of the body 32a is at the same position as the closed end of the body 32a, or is located outward in the axial direction from the closed end of the body 32a. In other words, when the pump device 1 is vertical, the upper end of the internal flow path of the discharge port 32c is located at a height higher than or equal to the upper inner surface of the body 32a.

[0025] The mounting portion 32d is formed in a part of the center of the other end of the body portion 32a. The mounting portion 32d protrudes toward the opening at one end of the body portion 32a. One end of the shaft seal member 23 is provided on the mounting portion 32d. The mounting portion 32d is formed in a cylindrical shape that protrudes axially within the body portion 32a, and is formed so that the pump shaft 12a can be inserted into its central part and a part of the shaft seal member 23 can be attached to its tip. For example, the tip of the mounting portion 32d is formed in a bottomed cylindrical shape so that, for example, the fixing ring of the shaft seal member 23 can be fixed to it.

[0026] The fourth flange 32f is formed on the outer circumferential surface of one open end of the body portion 32a. Multiple bolt holes 32e are formed in the fourth flange 32f, in which fastening members 90 are placed. The fourth flange 32f may be provided with multiple plate-shaped projections in which bolt holes 32e are formed, or it may be an annular or arc-shaped plate-shaped projection in which multiple bolt holes 32e are formed.

[0027] The second flange 31e and the fourth flange 32f are fixed by the fastening member 90, thereby fixing the suction casing 31 and the discharge casing 32 in the circumferential and axial directions, and sandwiching the return casing 33 between them, or sandwiching the return casing 33 and one or more intermediate casings 34 between them.

[0028] The support portion 32g is formed to support the return casing 33. The support portion 32g is formed, for example, by an end face formed on the other end side of the body portion 32a, beyond the end face of the opening end of the body portion 32a. That is, the support portion 32g is formed by a recessed surface from the end face of one end of the body portion 32a. The support portion 32g also has a first engaging portion 32i that engages with the return casing 33 in the circumferential direction. For example, the first engaging portion 32i is a recess. Multiple first engaging portions 32i are formed on the support portion 32g, for example, three at 90° intervals.

[0029] The fixing portion 32h is formed on the axial outer surface of the body portion 32a and includes a cylindrical fixing portion 32h to which the motor casing 11a of the motor 11 is fixed.

[0030] As shown in Figures 6 to 8, the return casing 33 comprises a first shroud 33a, a boss portion 33b, a second shroud 33c, a plurality of return blades (first return blades) 33d, a supported portion 33e, and a second engaging portion 33f. The return casing 33 rectifies the liquid discharged from the most secondary impeller 22 with the plurality of return blades 33d and guides it into the internal space of the body portion 32a of the discharge casing 32.

[0031] The first shroud 33a has an opening in the center into which the pump shaft 12a can be positioned. The main surface of the first shroud 33a opposite to the main surface facing the impeller 22 on the primary side, that is, the main surface on the body portion 32a side of the discharge casing 32, has a boss portion 33b formed on the central side.

[0032] The boss portion 33b is formed in a frustoconical cylindrical shape, on which the pump shaft 12a and a portion of the shaft sealing member 23 can be positioned. The outer diameter of the outer surface of the boss portion 33b gradually decreases as it moves away from the first shroud 33a. The outer surface of the boss portion 33b is curved, for example, with a predetermined radius of curvature.

[0033] The second shroud 33c is formed in a disc shape, for example, with an opening in the center, and moving away from the first shroud 33a from the outer edge towards the center.

[0034] The return vane 33d is provided between the first shroud 33a and the second shroud 33c. The central end of the return vane 33d is inclined, for example, with respect to the axial direction of the pump shaft 12a, so that the first shroud 33a side is closer to the center than the second shroud 33c side. Also, the axial height of the return vane 33d is, for example, higher towards the center than towards the outer edge. The return vane 33d is positioned on the body 31a of the suction casing 31 or the body 34a of the intermediate casing 34, and the radially outward end of the return vane 33d is spaced apart from the inner circumferential surfaces of the body 31a and 34a.

[0035] The supported portion 33e is formed on the outer peripheral edge of the second shroud 33c. The supported portion 33e is formed, for example, projecting from the outer peripheral edge of the outer surface of the second shroud 33c toward the secondary side in the axial direction. Specifically, the supported portion 33e has a first supported surface 33e1 formed on the discharge casing 32 side, which is the secondary side in the axial direction, a second supported surface 33e2 formed on the suction casing 31 side, which is the primary side in the axial direction, and an annular outer peripheral surface 33e3. The supported portion 33e is axially clamped between the support portion 31f of the suction casing 31 and the support portion 32g of the discharge casing 32, or axially clamped between the support portion 31f of the intermediate casing 34 (described later) and the support portion 32g of the discharge casing 32.

[0036] The first supported surface 33e1 abuts against the axial end face of the support portion 32g of the discharge casing 32. The second supported surface 33e2 abuts against either the axial end face of the support portion 31f of the suction casing 31 or the axial end face of the support portion 34e of the intermediate casing 34, which will be described later. The second supported surface 33e2 is located, for example, on the second shroud 33c side of the outer peripheral edge of the inner surface of the second shroud 33c that faces the first shroud 33a. In other words, the second supported surface 33e2 is recessed from the inner surface of the second shroud 33c. Therefore, the second supported surface 33e2 and the inner surface of the second shroud 33c form a step, and an outer peripheral surface is formed on the second shroud 33c. Therefore, when the supported portion 33e is sandwiched between the suction casing 31 or intermediate casing 34 and the discharge casing 32, the outer circumferential surface of the second shroud 33c is in close proximity to and facing the inner circumferential surface of the suction casing 31 or the inner circumferential surface of the intermediate casing 34.

[0037] When the first supported surface 33e1 of the outer circumferential surface 33e3 is in contact with the end face of the support portion 31f of the suction casing 31 and the second supported surface 33e2 of the discharge casing 32 is in contact with the end face of the support portion 32g, the upper end of the outer circumferential surface 33e3 is in close proximity to and facing the inner circumferential surface of the support portion 31f, or the upper end is in contact with the inner circumferential surface of the support portion 31f, the lower end is in close proximity to and facing or in contact with the inner circumferential surface of the support portion 32g, and the central end faces the seal groove 31a2 of the suction casing 31. In other words, the seal groove 31a2 of the suction casing 31, the end face 32a1 of the discharge casing 32, and the outer circumferential surface 33e3 of the return casing 33 form an annular seal chamber with a rectangular end face that accommodates the packing 35. Furthermore, if the pump device 1 is a multi-stage pump, the seal groove 34a2 of the intermediate casing 34 (described later), the end face 32a1 of the discharge casing 32, and the outer circumferential surface 33e3 of the return casing 33 form an annular seal chamber with a rectangular end face that accommodates the packing 35.

[0038] The second engaging portion 33f is formed on the outer surface of the second shroud 33c. The second engaging portion 33f engages with the first engaging portion 32i of the discharge casing 32 in the circumferential direction. For example, the second engaging portion 33f is a convex portion. The second engaging portion 33f is set to be the same number and arrangement as the first engaging portion 32i so that it can engage with the first engaging portion 32i. For example, multiple second engaging portions 33f are formed on the supported portion 33e, for example, three at 90° intervals. The second engaging portion 33f is provided, for example, on a recessed portion of the return casing 33, which is recessed from the surface of the supported portion 33e that contacts the support portion 32g of the discharge casing 32, for example, on the outer surface of the second shroud 33c adjacent to the supported portion 33e and recessed from the supported portion 33e.

[0039] As shown in Figure 3, the intermediate casing 34 comprises, for example, a body portion 34a, a third shroud 34b, a plurality of return vanes (second return vanes) 34c, a supported portion 34d, and a support portion 34e. The intermediate casing 34 is provided when the pump device 1 is a multi-stage pump and houses the impeller 22. The intermediate casing 34 rectifies the liquid discharged from the impeller 22, which is located adjacent to the primary side of the intermediate casing 34, with the plurality of return vanes 34c and guides it to the impeller 22 housed within it.

[0040] The body portion 34a has an opening at one end and an opening at the center of the other end, and is provided with a third shroud 34b and a plurality of return vanes 34c at the other end. That is, the opening at the other end of the body portion 34a, which is on the primary side in the direction of liquid flow, forms a mouth that guides the water guided by the plurality of return vanes 34c to the impeller 22 housed in the body portion 34a. The body portion 34a houses the impeller 22 and also houses the plurality of return vanes 34c of the return casing 33 or the return vanes 34c of another intermediate casing 34. The outer surface of the body portion 34a facing the third shroud 34b is inclined, for example, with respect to the axial direction of the pump shaft 12a and the main surface direction of the third shroud 34b. The body portion 34a has an end face 34a1 formed at one end that abuts against either the discharge casing 32 or the other intermediate casing 34, and a seal groove 34a2 formed on the end face 34a1. The end face 34a1 is formed in a planar, annular shape perpendicular to the axial direction. The seal groove 34a2 is, for example, an annular groove with a rectangular cross-section formed on the inner periphery of the end face 34a1. The end face 34a1 and seal groove 34a2 of the body portion 34a are formed in the same shape as, for example, the end face 31a1 and seal groove 31a2 of the suction casing 31.

[0041] The third shroud 34b is provided at the other end of the body 34a, which is on the primary side in the direction of water flow. The third shroud 34b has an opening in the center through which the pump shaft 12a can be positioned.

[0042] Multiple return vanes 34c are provided between the outer surface of the other end of the body 34a and the third shroud 34b. The central end of the return vane 34c extends, for example, in a direction along the axial direction of the pump shaft 12a, and the third shroud 34b side and the outer surface side of the body 34a of the return vane 34c are at the same radial position. Alternatively, the central end of the return vane 34c is inclined at a smaller angle of inclination with respect to the axial direction of the pump shaft 12a than the return vane 33d. Also, the axial height of the return vane 34c is, for example, higher on the central side than on the outer edge side. The return vane 34c is positioned on the body 31a of the suction casing 31 or the body 34a of another intermediate casing 34, and the radially outward end of the return vane 34c is spaced apart from the inner circumferential surface of the body 31a, 34a.

[0043] The supported portion 34d is provided on the outer circumferential surface of the other end of the body portion 34a. The supported portion 34d is supported by the end face 31a1 and the support portion 31f1, which are the ends of the suction casing 31. Specifically, the supported portion 34d has an end face 34d1 that can contact the end face 31a1 of the body portion 31a of the suction casing 31, and an outer circumferential surface 34d2 that can face the seal groove 31a2 of the suction casing 31. By positioning the supported portion 34d on the support portion 31f, a part of the outer circumferential surface 34d2 faces the seal groove 31a2, forming a seal chamber with the suction casing 31. That is, the supported portion 34d is formed in a shape that combines the end face 32a1 of the discharge casing 32 and the supported portion 33e of the return casing 33. Furthermore, if the pump device 1 is a multi-stage pump and has two or more intermediate casings 34, the supported portion 34d of the secondary intermediate casing 34 of adjacent intermediate casings 34 is supported by the end face 34a1 and support portion 34e, which are the end faces of one end of the other intermediate casing 34. Specifically, the supported portion 34d has an end face 34d1 that can abut against the end face 34a1 of the adjacent intermediate casing 34, and an outer peripheral surface 34d2 that can face the seal groove 34a2 of the adjacent intermediate casing 34. By positioning the supported portion 34d on the support portion 34e, a part of the outer peripheral surface 34d2 faces the seal groove 34a2, forming a seal chamber with the other intermediate casing 34. That is, the supported portion 34d is formed in a shape that combines the end face 32a1 of the discharge casing 32 and the supported portion 33e of the return casing 33.

[0044] The support portion 34e is formed, for example, at one open end of the body portion 34a. The support portion 34e is formed to support the supported portion 33e of the return casing 33 or the supported portion 34d of another intermediate casing 34. The support portion 34e is formed, for example, by an end face formed on the other end side of the body portion 34a, beyond the end face of the open end of the body portion 34a. That is, the support portion 34e is formed by a recessed surface from the end face of one end of the body portion 34a.

[0045] The packing 35 is a seal provided in a seal groove formed between the contact surfaces of each component of the casing 21 that need to be prevented from leaking liquid to the outside, and is, for example, an O-ring. For example, as shown in Figure 1, the packing 5 is provided in a seal chamber formed between the seal groove 31a2 of the suction casing 31, the end face 32a1 of the discharge casing 32, and the outer peripheral surface 33e3 of the supported portion 33e of the return casing 33, and seals the space between the suction casing 31 and the discharge casing 32.

[0046] Alternatively, as shown in Figures 2 and 3, if the casing 21 has an intermediate casing 34, the packing 35 is provided in the seal groove 31a2 of the suction casing 31, the seal groove formed between the end face 34d1 of the supported portion 34d of the intermediate casing 34 and the outer peripheral surface 34d2 of the supported portion 34d of the intermediate casing 34, and the seal chamber formed between the seal groove 34a2 of the intermediate casing 34, the end face 32a1 of the body portion 32a of the discharge casing 32 and the outer peripheral surface 33e3 of the supported portion 33e of the return casing 33. Each packing 35 seals the space between the suction casing 31 and the intermediate casing 34, and between the intermediate casing 34 and the discharge casing 32. Furthermore, if multiple intermediate casings 34 are provided, the packing 35 is further provided in a sealing chamber formed between the seal groove 34a2 of one of the adjacent intermediate casings 34 and the end face 34d1 and outer peripheral surface 34d2 of the supported portion 34d of the other intermediate casing 34, thereby sealing the space between the adjacent intermediate casings 34. In this way, the packing 35 is positioned in the sealing chamber formed by the seal grooves 31a2, 34a2 and the components covering the seal grooves 31a2, 34a2, and seals the space between the components of the casing 21 by adhering tightly to the wall surface forming the sealing chamber.

[0047] The impeller 22 comprises a fourth shroud 22a, a fifth shroud 22b, and a plurality of blades 22c. The fourth shroud 22a has a boss formed in its center, which has a hole for fixing the rotating shaft 12. The fifth shroud 22b has a suction port in its center. The plurality of blades 22c are provided between the fourth shroud 22a and the fifth shroud 22b, and the outer edges of the fourth shroud 22a and the fifth shroud 22b form discharge ports.

[0048] The shaft sealing member 23 is, for example, a mechanical seal. The shaft sealing member 23 is, for example, positioned at one end on the boss portion 33b of the return casing 33 and at the other end on the mounting portion 32d of the discharge casing 32. In a specific example, the shaft sealing member 23 comprises a rotating ring and a stationary ring, the rotating ring being fixed to the pump shaft 12a and positioned within the boss portion 33b, and the stationary ring being positioned on the mounting portion 32d.

[0049] Next, we will explain an example of the configuration of the pump device 1 as described above. As shown in Figure 2, the minimum inner diameter ΦD1 of the multiple return blades 33d of the return casing 33 is set to be larger than the minimum inner diameter ΦD2 of the multiple return blades 34c of the intermediate casing 34. This is because, while the return blades 34c of the intermediate casing 34 are shaped to return liquid to the suction port of the impeller 22, the return blades 33d of the return casing 33 also serve to guide liquid to the discharge casing 32. Therefore, making the minimum inner diameter of the return blades 33d larger than the minimum inner diameter of the return blades 34c helps to suppress obstruction of liquid flow.

[0050] As shown in Figure 2, the outer diameter of the impeller 22 is ΦD3, the outer diameter of the multiple return blades 33d, 34c of the return casing 33 or intermediate casing 34 is ΦD4, and the maximum inner diameter of the suction casing 31 or intermediate casing 34 is ΦD5. Here, the outer diameter ΦD4 of the multiple return blades 33d, 34c of the return casing 33 or intermediate casing 34 is either the diameter of the tangent circle passing through the outer end in the radial direction of the multiple return blades 33d, 34c, or the outer diameter of the shrouds 33a, 34b integrally provided with the multiple return blades 33d, 34c.

[0051] The dimensional ratio H1 (H1 = (ΦD3 / ΦD5) × 100) of the outer diameter ΦD3 of the impeller 22 to the maximum inner diameter ΦD5 of the suction casing 31 or intermediate casing 34 is preferably set to 50% or more and 70% or less. For example, at flow rates of 200 L / min, 300 L / min, and 400 L / min, if the dimensional ratio is less than 50%, the pump efficiency will be 1% or more worse compared to the case where it is between 50% and 70%, and if it is greater than 70%, the pump efficiency will be 2% or more worse. For this reason, it is preferable to set the dimensional ratio H1 to 50% or more and 70% or less.

[0052] Furthermore, the dimensional ratio H2 (H2 = (ΦD4 / ΦD5) × 100) of the outer diameter ΦD4 of the multiple return vanes 33d and 34c to the maximum inner diameter ΦD5 of the suction casing 31 or intermediate casing 34 is preferably set to 85% or more and 95% or less. For example, at flow rates of 200 L / min, 300 L / min, and 400 L / min, if the dimensional ratio is less than 85%, the pump efficiency will be 2% or more worse compared to the case where it is 85% or more and 95% or less, and if it is greater than 95%, the pump efficiency will be 2% or more worse. For this reason, it is preferable to set the dimensional ratio H2 to 85% or more and 95% or less.

[0053] The pump device 1 configured in this way has a return casing 33 positioned between the suction casing 31 and the discharge casing 32, and the return casing 33 can be selectively positioned between the intermediate casing 34 and the discharge casing 32. Therefore, the pump device 1 can share the suction casing 31, discharge casing 32, and return casing 33, which are components of the casing 21, whether it is a single-stage pump or a multi-stage pump. Furthermore, in the case of a multi-stage pump, the pump device 1 can be made into a pump with any number of stages by using an intermediate casing 34 of n minus 1 (n-1), which is the number of impeller blades 22. The pump device 1 has a high degree of design flexibility, and the number of parts and the management of parts can be reduced, thereby reducing manufacturing costs and management costs.

[0054] Furthermore, the pump device 1 is configured such that the discharge casing 32 forms an internal space facing the return casing 33 in the axial direction, and by having a shape without a volute, the radial shape of the pump 13 can be reduced, making it smaller compared to a pump device with a volute. In addition, by providing the discharge port 32c on the outer circumference of the body portion 32a of the discharge casing 32, it is possible to change the circumferential position of the discharge port 32c. For example, in the above example, the pump device 1 can change the circumferential position of the discharge port 32c by 90°.

[0055] Furthermore, since the discharge casing 32 has a dome-shaped internal space that faces the return casing 33 in the axial direction, the liquid that has passed through the return casing 33 can be efficiently guided to the discharge port 32c.

[0056] Furthermore, the discharge casing 32 has a support portion 32g and a first engaging portion 32i, and the return casing 33 has a supported portion 33e and a second engaging portion 33f. As a result, the return casing 33 is clamped in the axial direction by fastening the suction casing 31 and the discharge casing 32 with the fastening member 90, and its movement in the circumferential direction is restricted. Therefore, the return casing 33 can be easily fixed to the suction casing 31 and the discharge casing 32 in both the axial and circumferential directions.

[0057] Furthermore, since the protruding second engaging portion 33f is formed on the outer surface of the second shroud 33c of the return casing 33, it is possible to prevent the protrusion from being placed on the liquid flow path, thus preventing obstruction of the flow path.

[0058] Furthermore, since the return blades 33d have their central end inclined with respect to the axial direction and are curved or inclined upward in the axial direction from the radially outward side toward the center, obstruction of the flow of water moving into the discharge casing 32 can be suppressed. That is, since the secondary side of the return casing 33 is the internal space of the discharge casing 32 facing the return casing 33 in the axial direction, the radial flow of liquid passing through the multiple return blades 33d becomes an axial flow. Here, by inclining the central end of the return blades 33d to enlarge the opening and making the liquid flow between the return blades 33d inclined in the axial and radial directions, obstruction of the liquid flow can be suppressed.

[0059] Furthermore, the pump device 1 is a vertical pump with a rotating shaft 12 provided along the vertical direction, with the suction casing 31 positioned below and the discharge casing 32 positioned above. The discharge casing 32 is configured such that the height of the internal space of the body 32a, located above the return casing 33, is the same as or lower than the upper end of the flow path continuous with the internal space of the discharge port 32c. Therefore, if air bubbles are present in the liquid, it is possible to suppress the accumulation of air bubbles that have moved into the body 32a of the discharge casing 32. In addition, since the return casing 33 has a boss portion 33b on which the shaft seal member 23 can be placed, the axial space for placing the shaft seal member 23 becomes part of the boss portion 33b. Thus, the pump 13 can be made smaller in the axial direction.

[0060] Furthermore, since the return casing 33 does not have any other parts positioned outside the radially outward ends of the multiple return blades 33d, the shape of the mold can be simplified and sand can be easily removed when manufacturing the return casing 33 by casting. Also, when manufacturing the return casing 33 by pressing, drawing of the first shroud 33a is unnecessary. In this way, the return casing 33 can improve productivity compared to a shape in which some of the components are positioned radially outward of the return blades 33d.

[0061] According to the pump device 1 of the above embodiment, even if the number of impellers 22 is different, the components constituting the casing 21 can be shared.

[0062] The embodiments are not limited to the examples described above. For example, in the example of the pump device 1 having an intermediate casing 34 shown in Figure 2, the intermediate casing 34 has a configuration in which a third shroud 34b and a second return vane 34c are integrally included. However, the pump device 1 may also be configured to have a return casing 33 on the primary side of the intermediate casing 34. That is, the pump device 1 may have a configuration in which a return casing 33 is located between the intermediate casing 34 and the suction casing 31. In such a configuration, the return casing 33 may be located between the discharge casing 32 and the intermediate casing 34, and may also be located on the primary side of the intermediate casing 34, or it may be located on the primary side of the intermediate casing 34 instead of between the discharge casing 32 and the intermediate casing 34. Furthermore, when the return casing 33 is located on the primary side of the intermediate casing 34, the intermediate casing 34 may have a plurality of second return vanes 34c, or it may not have a plurality of second return vanes 34c. By sandwiching the return casing 33 on the primary side of the intermediate casing 34, the same effects as in the above-described embodiment can be obtained. Furthermore, by using a separate return casing 33, the radial length of the first shroud 33a of the return casing 33 can be easily changed to a length that allows for highly efficient discharge. In addition, multiple intermediate casings 34 and return casings 33 may be provided to create a multi-stage configuration.

[0063] It should be noted that the present invention is not limited to the embodiments described above, and can be modified in various ways during implementation without departing from its essence. Furthermore, each embodiment may be combined as appropriate, and in that case, the combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple constituent elements disclosed. For example, if the problem can be solved and effects obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, then the configuration with these deleted constituent elements can be extracted as an invention. The following is a description equivalent to the invention described in the original claims of this application. [1] The axis of rotation and An impeller provided on the aforementioned rotating shaft, A suction casing housing the impeller, A discharge casing is provided on the secondary side of the impeller, forming a flow path with the suction casing and having a discharge port, A return casing is held within the flow path and has a first return blade provided between the secondary side of the impeller and the discharge casing, and a supported portion formed to be sandwiched between the suction casing and the discharge casing. A pumping device equipped with the following features. [2] The pump device according to [1], wherein the supported portion is sandwiched between the suction casing and the discharge casing. [3] Further comprising an intermediate casing for housing the impeller, provided between the suction casing and the return casing and formed so as to be able to sandwich the return casing between the discharge casings, The supported portion is sandwiched between the intermediate casing and one of the discharge casing, the suction casing, and the other intermediate casings, according to the pump device described in [1] or [2]. [4] The discharge casing has a support portion that abuts the supported portion and a first engaging portion provided on the support portion, The pump device according to [1], wherein the return casing has a second engaging portion that engages with the first engaging portion in the circumferential direction. [5] Multiple impellers are provided, The casing further comprises an intermediate casing provided between the suction casing and the return casing, formed so as to allow the return casing to be sandwiched between the discharge casings, which houses the impeller and has a second return blade that guides water from the primary side impeller to the impeller it houses, The pump device according to [1], wherein the minimum inner diameter of the first return vane is greater than the minimum inner diameter of the second return vane. [6] The first return blade has an end on the central side that is inclined with respect to the axial direction, and is curved or inclined upward from the radially outward side toward the central side, The pump device according to [5], wherein the second return vane has an end on the central side that is aligned with the axial direction, or is inclined with respect to the axial direction at a smaller angle of inclination than the first return vane. [7] The pump device according to [1], wherein the outer diameter of the impeller is 50% or more and 70% or less of the maximum inner diameter of the suction casing. [8] The pump device according to [1], wherein the outer diameter of the first return vane is 85% or more and 95% or less of the maximum inner diameter of the suction casing. [Explanation of Symbols]

[0064] 1...Pump device, 11...Motor, 11a...Motor casing, 11b...Motor shaft, 12...Rotating shaft, 12a...Pump shaft, 12b...Shaft coupling, 13...Pump, 21...Casing, 22...Impeller, 22a...Fourth shroud, 22b...Fifth shroud, 22c...Blades, 23...Shaft seal member, 31...Suction casing, 31a...Body, 31b...First flange, 31c...Suction port, 31d...Bolt hole, 31e...Second flange, 31f...Support part, 32...Discharge casing, 32a...Body, 32b...Third flange, 3 2c...Discharge port, 32d...Mounting part, 32e...Bolt hole, 32f...Fourth flange, 32g...Support part, 32h...Fixing part, 32i...First engaging part, 33...Return casing, 33a...First shroud, 33b...Boss part, 33c...Second shroud, 33d...Return vane (First return vane), 33e...Supported part, 33f...Second engaging part, 34...Intermediate casing, 34a...Body part, 34b...Third shroud, 34c...Return vane (Second return vane), 34d...Supported part, 34e...Support part, 35...Packing, 90...Fastening member.

Claims

1. The axis of rotation and An impeller provided on the aforementioned rotating shaft, A suction casing housing the impeller, A discharge casing is provided on the secondary side of the impeller, forming a flow path with the suction casing and having a discharge port, A return casing is held within the flow path and has a first return blade provided between the secondary side of the impeller and the discharge casing, and a supported portion formed to be sandwiched between the suction casing and the discharge casing. Equipped with, Multiple impellers are provided, An intermediate casing is provided between the suction casing and the return casing, and is formed so as to be able to sandwich the return casing between the discharge casings, and houses the impeller, and further comprises an intermediate casing having a second return blade that guides water from the primary side impeller to the housed impeller, A pump device in which the minimum inner diameter of the first return vane is greater than the minimum inner diameter of the second return vane.

2. The first return blade has an end on the central side that is inclined with respect to the axial direction, and is curved or inclined upward from the radially outward side toward the central side. The pump device according to claim 1, wherein the end of the second return vane on the central side is aligned with the axial direction, or is inclined with respect to the axial direction at a smaller angle of inclination than that of the first return vane.

3. A rotating shaft and An impeller provided on the aforementioned rotating shaft, A suction casing housing the impeller, A discharge casing is provided on the secondary side of the impeller, forming a flow path with the suction casing and having a discharge port, A return casing is held within the flow path and has a return blade provided between the secondary side of the impeller and the discharge casing, and a supported portion formed to be sandwiched between the suction casing and the discharge casing. Equipped with, The return vane is positioned on the body of the intake casing, A pump device wherein the radial end of the return blade is spaced apart from the inner circumferential surface of the body.

4. The return casing comprises a first shroud and a second shroud, The return vane is provided between the first shroud and the second shroud, The supported portion is formed on the outer peripheral edge of the second shroud and is sandwiched between the suction casing and the discharge casing. The pump device according to claim 3, wherein when the supported portion is sandwiched between the suction casing and the discharge casing, the outer circumferential surface of the second shroud is in close proximity to and facing the inner circumferential surface of the suction casing.

5. A rotating shaft and An impeller provided on the aforementioned rotating shaft, A suction casing housing the impeller, A discharge casing is provided on the secondary side of the impeller, forming a flow path with the suction casing and having a discharge port, An intermediate casing provided between the suction casing and the discharge casing, A return casing is held within the flow path and has a return blade provided between the secondary side of the impeller and the discharge casing, and a supported portion formed to be sandwiched between the suction casing and the discharge casing. Equipped with, The supported portion of the return casing is sandwiched between the intermediate casing and the discharge casing. The return vane is positioned on the body of the intermediate casing. A pump device in which the radially outward end of the return blade is spaced apart from the inner circumferential surface of the body.

6. The return casing comprises a first shroud and a second shroud, The return vane is provided between the first shroud and the second shroud, The supported portion is formed on the outer peripheral edge of the second shroud and is sandwiched between the intermediate casing and the discharge casing. The pump device according to claim 5, wherein when the supported portion is sandwiched between the intermediate casing and the discharge casing, the outer circumferential surface of the second shroud is in close proximity to and facing the inner circumferential surface of the intermediate casing.

7. The pump device according to claim 4 or claim 6, wherein the supported portion is formed to protrude axially from the outer peripheral edge of the second shroud.

8. The discharge casing has a support portion that abuts against the supported portion, and a first engaging portion provided on the support portion. The pump device according to claim 1, claim 3, or claim 5, wherein the return casing has a second engaging portion that engages with the first engaging portion in the circumferential direction.

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