Pump 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 pumping liquid. [Background technology]

[0002] Conventionally, as centrifugal pumps, single-stage pump devices having a single impeller and multi-stage pump devices having multiple impellers have been known (see, for example, Patent Documents 1 to 3). In such pump devices, when the number of impellers is changed, the casing must also have a different shape in order to satisfy the pumping performance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-324964 [Patent Document 2] JP 2003-184778 A [Patent Document 3] JP 2005-188389 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned pump device, since the casing needs to be shaped differently depending on the number of impellers, the number of parts increases, which increases the manufacturing and management costs. For this reason, there is a demand for standardization of parts while still satisfying the pumping performance.

[0005] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a pump device that allows the components constituting the casing to be shared even if the number of impellers is different. [Means for solving the problem]

[0006] According to one aspect of the present invention, a pump device includes a rotating shaft, an impeller provided on the rotating shaft, a suction casing that houses 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 that has a first return vane provided between the secondary side of the impeller and the discharge casing and is formed so that it can be sandwiched between the suction casing and the discharge casing. Effect of the Invention

[0007] According to the present invention, it is possible to provide a highly efficient pump device that allows the use of a common casing. [Brief description of the drawings]

[0008] [Figure 1] 1 is a side view, partially in cross section, showing a configuration of a pump device according to an embodiment of the present invention, illustrating an example of a single-stage pump. [Diagram 2] 1 is a side view, partially in cross section, showing a configuration of a pump device according to an embodiment of the present invention, which is an example of a multi-stage pump. [Diagram 3] FIG. 2 is an exploded cross-sectional view showing a schematic configuration of a casing used in the pump device. [Figure 4] FIG. 4 is a cross-sectional view showing the configuration of a discharge casing of the casing. [Diagram 5] FIG. [Figure 6] FIG. 4 is a cross-sectional view showing the configuration of a return casing of the casing. [Figure 7] FIG. [Figure 8] FIG. 4 is a bottom view showing the configuration of the return casing with some parts omitted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0010] 1 and 2, the pump device 1 is a centrifugal pump, and is a single-stage pump having a single impeller 22, or a multi-stage pump having a plurality of impellers 22. The pump device 1 is, for example, a vertical pump in which the rotating shaft 12 is used in an orientation along the vertical direction (gravity direction), but may also be a horizontal pump in which the rotating shaft 12 is used in an orientation along the horizontal direction (horizontal direction). As a specific example, as shown in FIGS. 1 and 2, the pump device 1 includes 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 a rotating shaft 12. The motor 11 includes, for example, a motor casing 11a, a stator provided in the motor casing 11a, a rotor that rotates relative to the stator, and a motor shaft 11b fixed to the rotor. In addition, for example, the motor 11 includes a cooling fan that rotates due to the rotation of the motor shaft 11b.

[0012] The rotating shaft 12 rotates an impeller 22 of the pump 13, which will be described later, by the rotation of the rotor of the motor 11. The rotating shaft 12 includes, 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 thereto. Note that the rotating shaft 12 may be configured not to include the pump shaft 12a, and the motor shaft 11b may extend into a casing 21 of the pump 13, which will be described later, and the impeller 22 may be directly fixed to the motor shaft 11b.

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

[0014] 1 and 2, the casing 21 includes a suction casing 31, a discharge casing 32, a return casing 33, and a packing 35. By connecting the suction casing 31, the return casing 33, and the discharge casing 32, the casing 21 forms a flow path inside, through which liquid flows that is sucked into the impeller 22 and pressurized by the impeller 22. As a specific example, 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 the flow path by being sandwiched between the suction casing 31 and the discharge casing 32.

[0015] In addition, when the pump device 1 is a multi-stage pump, as shown in Fig. 2, the casing 21 further includes intermediate casings 34, the number of which is one less than the number of impellers 22. For example, as shown in Fig. 1, the casing 21 is integrally formed by sandwiching the return casing 33 in the casing 21 between the suction casing 31 and the discharge casing 32, or by sandwiching the return casing 33 in the casing 21 between 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. The return casing 33 and / or the intermediate casing 34 may be fixed to the suction casing 31 and / or the discharge casing 32 with the fastening member 90.

[0016] Also, as shown in Figures 2 and 3, when the casing 21 is configured to have an intermediate casing 34, the suction casing 31 is arranged on the most primary side in the direction of liquid flow, followed by one or more intermediate casings 34, the return casing 33 is arranged on the secondary side of the intermediate casing 34, and the discharge casing 32 is arranged on the secondary side of the return casing 33.

[0017] The suction casing 31 is formed to be capable of housing the impeller 22. The suction casing 31 is formed to be capable of disposing one of the return casing 33 and the intermediate casing 34 on the motor 11 side. As shown in Fig. 3, the suction casing 31 includes, for example, a body 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 31a accommodates the impeller 22 and also accommodates a part of the return casing 33 or the intermediate casing 34. One end of the body 31a is open, and the other end of the body 31a is provided with a suction port 31c. The body 31a has an end face 31a1 formed at one end and abutting against one of the discharge casing 32 and the intermediate casing 34, and a seal groove 31a2 formed in the end face 31a1. The end face 31a1 is formed in a circular flat shape perpendicular to the axial direction. The seal groove 31a2 is, for example, an annular groove formed on the inner peripheral edge of the end face 31a1 and having a rectangular cross section.

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

[0020] The second flange 31e is formed with a plurality of bolt holes 31d in which the fastening members 90 are disposed. The second flange 31e is, for example, a plate-like protrusion in which the bolt holes 31d are formed at a plurality of locations, or an annular or arc-shaped plate-like protrusion in which the plurality of bolt holes 31d are formed.

[0021] The support portion 31f is formed to be capable of supporting the return casing 33 and the intermediate casing 34. The support portion 31f is formed, for example, by an end face that is formed on the other end side of the body portion 31a relative to the end face of one end where the body portion 31a opens. That is, the support portion 31f is formed by a surface recessed 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, an attachment portion 32d, a fourth flange 32f having a bolt hole 32e formed therein, a support portion 32g, and a fixing portion 32h.

[0023] The body 32a is open at one end and forms a space on the secondary side of the return casing 33 in the liquid flow direction. The body 32a disposes the pump shaft 12a and the shaft seal member 23 at the center of the space formed on the secondary side of the return casing 33. A discharge port 32c is provided at a part of the outer periphery in the circumferential direction of the body 32a. The body 32a is formed in a dome shape, and the dome-shaped internal space is cylindrically recessed at the center by the mounting portion 32d. The internal space of the body 32a faces the return casing 33 in the axial direction. The body 32a has an end face 32a1 formed at one end and 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 31a of the suction casing 31 and to face against the seal groove 31a2 of the body 31a of the suction casing 31. In addition, when 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 an end face 34a1 of the body portion 34a of the intermediate casing 34, which will be described later, and to be able to face a seal groove 34a2 of the body portion 34a of the intermediate casing 34, which will be described later.

[0024] The discharge port 32c is connected to a pipe via, for example, the third flange 32b, and discharges the liquid pressurized by 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 located 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 a vertical type, the upper end of the internal flow path of the discharge port 32c is located at a height position equal to or higher than 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 an 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 protruding in the axial direction within the body portion 32a, and is formed so that the pump shaft 12a can be inserted into the central portion and a part of the shaft seal member 23 can be attached to the tip. For example, the tip of the mounting portion 32d is formed in a cylindrical shape with a bottom so that, for example, a fixed ring of the shaft seal member 23 can be fixed thereto.

[0026] The fourth flange 32f is formed on the outer peripheral surface of one open end of the body 32a. The fourth flange 32f is formed with a plurality of bolt holes 32e in which the fastening members 90 are disposed. The fourth flange 32f is, for example, a plate-like protrusion in which the bolt holes 32e are formed at a plurality of locations, or an annular or arc-shaped plate-like protrusion in which the plurality of bolt holes 32e are formed.

[0027] The second flange 31e and the fourth flange 32f are fixed by fastening members 90, thereby fixing the suction casing 31 and the discharge casing 32 circumferentially and axially and sandwiching the return casing 33 therebetween, or sandwiching the return casing 33 and one or more intermediate casings 34 therebetween.

[0028] The support portion 32g is formed so as to be able 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 relative to the end face of one end where the body portion 32a opens. That is, the support portion 32g is formed by a surface recessed from the end face of one end of the body portion 32a. The support portion 32g is also formed with a first engagement portion 32i that engages with the return casing 33 in the circumferential direction. For example, the first engagement portion 32i is a recess. A plurality of first engagement portions 32i, for example, three first engagement portions 32i are formed on the support portion 32g at 90° intervals.

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

[0030] 6 to 8, the return casing 33 includes a first shroud 33a, a boss portion 33b, a second shroud 33c, a plurality of return vanes (first return vanes) 33d, a supported portion 33e, and a second engaging portion 33f. The return casing 33 straightens the liquid discharged from the most secondary side impeller 22 with the plurality of return vanes 33d, and guides the liquid to the internal space of the body portion 32a of the discharge casing 32.

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

[0032] The boss portion 33b is formed in a truncated cone-shaped cylinder in which the pump shaft 12a and a part of the shaft seal member 23 can be disposed. The outer diameter of the outer peripheral surface of the boss portion 33b gradually decreases as it becomes more distant from the first shroud 33a. The outer peripheral surface of the boss portion 33b is curved, for example, with a predetermined radius of curvature.

[0033] The second shroud 33c is formed, for example, in a disk shape that is open at the center and moves away from the first shroud 33a from the outer circumferential edge side toward the center side.

[0034] The return vane 33d is provided between the first shroud 33a and the second shroud 33c. The end of the return vane 33d on the central side is inclined with respect to the axial direction of the pump shaft 12a, for example, so that the first shroud 33a side is closer to the central side than the second shroud 33c side. Also, the axial height of the return vane 33d is, for example, higher on the central side than on the outer edge side. The return vane 33d is disposed in the body part 31a of the suction casing 31 or the body part 34a of the intermediate casing 34, and the radially outer end of the return vane 33d is spaced apart from the inner circumferential surfaces of the body parts 31a, 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, protruding from the outer peripheral edge of the outer surface of the second shroud 33c toward the secondary side in the axial direction. As a specific example, 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 sandwiched in the axial direction between a support portion 31f of the suction casing 31 and a support portion 32g of the discharge casing 32, or is sandwiched in the axial direction between a support portion 31f of the intermediate casing 34 (described later) and a support portion 32g of the discharge casing 32.

[0036] The first supported surface 33e1 abuts against an axial end face of the support portion 32g of the discharge casing 32. The second supported surface 33e2 abuts against one of the axial end face of the support portion 31f of the suction casing 31 and the axial end face of a support portion 34e (described later) of the intermediate casing 34. The second supported surface 33e2 is located, for example, closer to the second shroud 33c than the outer circumferential edge of the inner surface of the second shroud 33c facing the first shroud 33a. In other words, the second supported surface 33e2 is recessed from the inner surface of the second shroud 33c. Thus, the second supported surface 33e2 and the inner surface of the second shroud 33c form a step shape, and an outer circumferential surface is formed on the second shroud 33c. Therefore, when the supported portion 33e is clamped between the suction casing 31 or the intermediate casing 34 and the discharge casing 32, the outer peripheral surface of the second shroud 33c closely faces the inner peripheral surface of the suction casing 31 or the inner peripheral surface of the intermediate casing 34.

[0037] When the first supported surface 33e1 is in contact with the end face of the support portion 31f of the suction casing 31 and the second supported surface 33e2 is in contact with the end face of the support portion 32g of the discharge casing 32, the upper end side of the outer circumferential surface 33e3 faces closely to the inner circumferential surface of the support portion 31f, or the upper end side abuts against the inner circumferential surface of the support portion 31f, the lower end side faces closely to the inner circumferential surface of the support portion 32g or abuts against it, and the center side 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 houses the packing 35. In addition, when the pump device 1 is a multi-stage pump, a seal groove 34a2 (described later) of the intermediate casing 34, an end face 32a1 of the discharge casing 32, and an outer peripheral surface 33e3 of the return casing 33 form an annular seal chamber with a rectangular end face that accommodates the gasket 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 portions 33f are set to the same number and arrangement as the first engaging portions 32i so as to be able to engage with the first engaging portions 32i. For example, a plurality of the second engaging portions 33f are formed on the supported portion 33e, for example, three second engaging portions 33f are formed at 90° intervals. The second engaging portions 33f are provided, for example, on a portion of the return casing 33 that is recessed from the surface of the supported portion 33e that abuts against the support portion 32g of the discharge casing 32, for example, on an outer surface adjacent to the supported portion 33e of the second shroud 33c and recessed from the supported portion 33e.

[0039] 3, the intermediate casing 34 includes, 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 supporting 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 straightens the liquid discharged from the impeller 22 arranged adjacent to the primary side of the intermediate casing 34 with the plurality of return vanes 34c, and guides the liquid to the housed impeller 22.

[0040] The body 34a has one open end and a central open 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 34a, which is the primary side in the flow direction of the liquid, forms a mouth that guides water guided by the plurality of return vanes 34c to the impeller 22 housed in the body 34a. The body 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 34a facing the third shroud 34b is inclined, for example, with respect to the axial direction of the pump shaft 12a and the direction of the main surface of the third shroud 34b. The body 34a has an end face 34a1 formed at one end and abutting against the discharge casing 32 or one of the intermediate casings 34, and a seal groove 34a2 formed in the end face 34a1. The end face 34a1 is formed in a circular flat shape perpendicular to the axial direction. The seal groove 34a2 is, for example, an annular groove formed on the inner peripheral edge of the end face 34a1 and having a rectangular cross section. The end face 34a1 and the seal groove 34a2 of the body 34a are formed, for example, in the same shape as the end face 31a1 and the 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 the primary side in the water flow direction. The third shroud 34b has an opening at its center, in which the pump shaft 12a can be disposed.

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

[0043] The supported portion 34d is provided on the outer peripheral surface of the other end side of the body portion 34a. The supported portion 34d is supported by the end face 31a1, which is the end of the suction casing 31, and the support portion 31f1. As a specific example, the supported portion 34d has an end face 34d1 that can abut against the end face 31a1 of the body portion 31a of the suction casing 31, and an outer peripheral surface 34d2 that can face the seal groove 31a2 of the suction casing 31. The supported portion 34d is disposed on the support portion 31f, so that a part of the outer peripheral 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. In addition, when 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 among the adjacent intermediate casings 34 is supported by the end face 34a1, which is an end portion on one end side of the other intermediate casing 34, and the support portion 34e. As a specific example, the supported portion 34d has an end face 34d1 that can abut against the end face 34a1 of the other adjacent intermediate casing 34, and an outer circumferential surface 34d2 that can face the seal groove 34a2 of the other adjacent intermediate casing 34. The supported portion 34d is disposed on the support portion 34e, so that a part of the outer circumferential 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 so as to be able 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 that is formed on the other end side of the body portion 34a relative to the end face of the one open end of the body portion 34a. In other words, the support portion 34e is formed by a surface recessed from the end face of one end of the body portion 34a.

[0045] The packing 35 is a seal, such as an O-ring, provided in a seal groove formed between the abutting surfaces of the components of the casing 21 that need to prevent leakage of liquid to the outside. For example, as shown in FIG. 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 circumferential surface 33e3 of the supported portion 33e of the return casing 33, and seals the gap between the suction casing 31 and the discharge casing 32.

[0046] 2 and 3, when the casing 21 has an intermediate casing 34, the packing 35 is provided in each of 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 circumferential surface 34d2 of the supported portion 34d of the intermediate casing 34, and 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 circumferential surface 33e3 of the supported portion 33e of the return casing 33. Each packing 35 seals between the suction casing 31 and the intermediate casing 34, and between the intermediate casing 34 and the discharge casing 32. Furthermore, when a plurality of intermediate casings 34 are provided, the packing 35 is further provided in a seal chamber formed between the seal groove 34a2 of one of the adjacent intermediate casings 34 and the end face 34d1 and the outer circumferential face 34d2 of the supported portion 34d of the other (different) intermediate casing 34, and seals between the adjacent intermediate casings 34. In this way, the packing 35 is disposed in the seal chamber formed by the seal grooves 31a2, 34a2 and the components covering the seal grooves 31a2, 34a2, and seals between the components of the casing 21 by coming into close contact with the wall surfaces that form the seal chamber.

[0047] The impeller 22 includes a fourth shroud 22a, a fifth shroud 22b, and a plurality of vanes 22c. The fourth shroud 22a is provided with a boss having a hole in the center to which the rotary shaft 12 is fixed. A suction port is formed in the center of the fifth shroud 22b. A plurality of vanes 22c are provided between the fourth shroud 22a and the fifth shroud 22b, and the outer circumferential edges of the fourth shroud 22a and the fifth shroud 22b form a discharge port.

[0048] The shaft seal member 23 is, for example, a mechanical seal. For example, one end of the shaft seal member 23 is disposed in the boss portion 33b of the return casing 33, and the other end is disposed in the mounting portion 32d of the discharge casing 32. As a specific example, the shaft seal member 23 includes a rotating ring and a fixed ring, the rotating ring is fixed to the pump shaft 12a and disposed in the boss portion 33b, and the fixed ring is disposed in the mounting portion 32d.

[0049] Next, an example of the configuration of the pump device 1 thus configured will be described. 2, the minimum inner diameter ΦD1 of the multiple return vanes 33d of the return casing 33 is set to be larger than the minimum inner diameter ΦD2 of the multiple return vanes 34c of the intermediate casing 34. This is because, while the return vanes 34c of the intermediate casing 34 are shaped to return to the suction port of the impeller 22, the return vanes 33d of the return casing 33 also serve to guide the liquid to the discharge casing 32, and therefore, making the minimum inner diameter of the return vanes 33d larger than the minimum inner diameter of the return vanes 34c can prevent the flow of the liquid from being obstructed.

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

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

[0052] In addition, the size ratio H2 (H2=(ΦD4 / ΦD5)×100) of the outer diameter ΦD4 of the multiple return vanes 33d, 34c to the maximum inner diameter dimension ΦD5 of the suction casing 31 or the intermediate casing 34 is preferably set to 85% or more and 95% or less. As an example, when the flow rate is 200 L / min, 300 L / min, or 400 L / min, if the size ratio is less than 85%, the pump efficiency is reduced by 2% or more compared to when the size ratio is between 85% and 95% or less, and if the size ratio is greater than 95%, the pump efficiency is reduced by 2% or more. For this reason, it is preferable to set the size ratio H2 to 85% or more and 95% or less.

[0053] The pump device 1 thus configured has a return casing 33 disposed between the suction casing 31 and the discharge casing 32, and is configured so that the return casing 33 can be selectively disposed between the intermediate casing 34 and the discharge casing 32. Therefore, whether the pump device 1 is a single-stage pump or a multi-stage pump, the suction casing 31, the discharge casing 32, and the return casing 33, which are components constituting the casing 21, can be shared. In addition, 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 intermediate casings 34 whose number is n minus 1 (n-1), which is the number n of the impellers 22. The pump device 1 has a high degree of freedom in design, and can reduce the types of parts and the management of parts, 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 does not have a volute, which allows the radial shape of the pump 13 to be small, making it possible to make the pump device 1 smaller than a pump device having a volute. Furthermore, the discharge port 32c is provided on the outer periphery of the body portion 32a of the discharge casing 32, making it possible to change the circumferential position of the discharge port 32c. For example, in the above example, the pump device 1 can shift the circumferential position of the discharge port 32c by 90°.

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

[0056] Further, 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 members 90, and 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 the axial direction and the circumferential direction.

[0057] Furthermore, since the second engagement portion 33f, which is a convex portion, is formed on the outer surface of the second shroud 33c of the return casing 33, it is possible to prevent a convex portion from being provided on the liquid flow path, thereby preventing obstruction of the flow path.

[0058] In addition, the end of the return vane 33d on the center side is inclined with respect to the axial direction, and is curved or inclined axially upward from the radially outer side toward the center side, so that 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 vanes 33d becomes a flow in the axial direction. Here, obstruction of the flow of liquid can be suppressed by inclining the end of the return vane 33d on the center side to enlarge the opening and by making the flow of liquid between the return vanes 33d a flow inclined in the axial and radial directions.

[0059] The pump device 1 is a vertical pump in which the rotating shaft 12 is arranged in the vertical direction, the suction casing 31 is arranged below, and the discharge casing 32 is arranged above. The discharge casing 32 is configured so 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 connected to the internal space of the discharge port 32c. Therefore, when air bubbles are contained in the liquid, the air bubbles that have moved to the body 32a of the discharge casing 32 can be prevented from accumulating. The return casing 33 has a boss portion 33b in which the shaft seal member 23 can be arranged, and therefore the axial space for arranging the shaft seal member 23 becomes part of the boss portion 33b. Therefore, the pump 13 can be made smaller in the axial direction.

[0060] In addition, since the return casing 33 has no other parts disposed outside the radially outer ends of the return vanes 33d, the shape of the mold can be simplified and sand can be easily removed when the return casing 33 is manufactured by casting. In addition, when the return casing 33 is manufactured by pressing, drawing of the first shroud 33a is not required. In this way, the return casing 33 can improve productivity compared to a shape in which a part of the configuration is provided radially outward of the return vanes 33d.

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

[0062] The embodiment is not limited to the above-mentioned example. For example, in the example of the pump device 1 having the intermediate casing 34 shown in FIG. 2, the intermediate casing 34 is configured to integrally include the third shroud 34b and the second return vane 34c. However, the pump device 1 may be configured to have the return casing 33 provided on the primary side of the intermediate casing 34, for example. That is, the pump device 1 may be configured to have the return casing 33 between the intermediate casing 34 and the suction casing 31. In such a configuration, the return casing 33 may be provided between the discharge casing 32 and the intermediate casing 34, and may further be provided on the primary side of the intermediate casing 34, or may be provided on the primary side of the intermediate casing 34 instead of between the discharge casing 32 and the intermediate casing 34. In addition, when the return casing 33 is provided on the primary side of the intermediate casing 34, the intermediate casing 34 may have a plurality of second return vanes 34c, or 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, it is possible to obtain the same effect as in the above-mentioned embodiment. Furthermore, by providing a separate return casing 33, it is possible to easily change the radial length of the first shroud 33a of the return casing 33 to a length that provides high discharge efficiency. Note that a plurality of intermediate casings 34 and return casings 33 may be provided to form a multi-stage configuration.

[0063] The present invention is not limited to the above-mentioned embodiment, and can be modified in various ways without departing from the gist of the present invention. The embodiments may be combined as appropriate, and in that case, the combined effect can be obtained. Furthermore, the above-mentioned embodiment includes various inventions, and various inventions can be extracted by combinations selected from the multiple components disclosed. For example, if the problem can be solved and the effect can be obtained even if some components are deleted from all the components shown in the embodiment, the configuration from which the components are deleted can be extracted as an invention. [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...blade, 23...shaft seal member, 31...suction casing, 31a...body portion, 31b...first flange, 31c...suction port, 31d...bolt hole, 31e...second flange, 31f...support portion, 32...discharge casing, 32a...body portion, 32b...third flange, 3 2c...discharge port, 32d...mounting portion, 32e...bolt hole, 32f...fourth flange, 32g...support portion, 32h...fixing portion, 32i...first engagement portion, 33...return casing, 33a...first shroud, 33b...boss portion, 33c...second shroud, 33d...return blade (first return blade), 33e...supported portion, 33f...second engagement portion, 34...intermediate casing, 34a...body portion, 34b...third shroud, 34c...return blade (second return blade), 34d...supported portion, 34e...support portion, 35...packing, 90...fastening member.

Claims

1. A rotation axis; an impeller provided on the rotating shaft; a suction casing that houses the impeller; a discharge casing provided on a secondary side of the impeller, forming a flow passage together with the suction casing and having a discharge port; a return casing that has a first return vane provided between the secondary side of the impeller and the discharge casing, and a supported portion that is formed so as to be sandwiched between the suction casing and the discharge casing, and is held in the flow path; A pump device comprising:

2. The pump device according to claim 1 , wherein the supported portion is sandwiched between the suction casing and the discharge casing.

3. The compressor further includes an intermediate casing that houses the impeller and is provided between the suction casing and the return casing and is configured so that the return casing can be sandwiched between the discharge casing and the intermediate casing.

3. The pump device according to claim 1, wherein the supported portion is sandwiched between the intermediate casing and any one of the discharge casing, the suction casing and another intermediate casing.

4. the discharge casing has a support portion that comes into contact with the supported portion and a first engagement portion that is provided on the support portion, The pump device according to claim 1 , wherein the return casing has a second engagement portion that engages with the first engagement portion in a circumferential direction.

5. A plurality of the impellers are provided, The compressor further includes an intermediate casing that is provided between the suction casing and the return casing and is formed so that the return casing can be sandwiched between the suction casing and the discharge casing, the intermediate casing houses the impeller and has a second return vane that guides water from the primary side impeller to the impeller that it houses; The pump apparatus of claim 1 , wherein a minimum inner diameter of the first return blade is greater than a minimum inner diameter of the second return blade.

6. The first return blade has a center side end inclined with respect to the axial direction, and is curved or inclined upward from a radially outer side toward the center side, The pump device according to claim 5 , wherein the end portion of the second return blade on the center side is aligned along the axial direction or is inclined with respect to the axial direction at an inclination angle smaller than that of the first return blade.

7. 2. The pump apparatus according to claim 1, wherein an outer diameter of the impeller is 50% or more and 70% or less of a maximum inner diameter dimension of the suction casing.

8. The pump apparatus according to claim 1 , wherein an outer diameter of the first return blade is 85% or more and 95% or less of a maximum inner diameter of the suction casing.

Images