JP6582086B1 - Pump device and pump casing - Google Patents

Abstract

A pump device and a pump casing capable of obtaining high pump efficiency are provided. A pump device according to an embodiment includes a first impeller configured to be rotatable, a second impeller disposed in one axial direction of the first impeller, and the first impeller. A first intermediate casing to be accommodated; a second intermediate casing to accommodate the second impeller; and the first intermediate casing and the second intermediate casing. A connection casing that communicates with the outflow port and forms a flow path that communicates with the inflow port of the second impeller. [Selection] Figure 1

Description

  The present invention relates to a multistage pump device and a pump casing in which a plurality of impellers are arranged.

  As a pump device, a multi-stage pump device in which a plurality of impellers are arranged is known. The pump device includes, for example, a plurality of impellers that are rotationally driven by a motor, and a pump casing in which a suction port and a discharge port are formed. An inflow port is provided in the center of the impeller, and an outflow port is formed on the outer periphery of the impeller. The pump casing includes a cylindrical portion provided on the outer periphery of the impeller, and a guide flow path having guide vanes for guiding fluid from the impeller to the next-stage impeller. When the impeller is rotated by the motor connected to the rotation shaft of the impeller, the fluid is discharged from the outlet of the outer periphery of the impeller, and the guide channel having the guide vanes and the return channel having the return vanes are provided. It is guided to the inlet of the next stage impeller by the pump casing to be formed.

Japanese Patent Laying-Open No. 2015-28314

  In such a pump device, when the primary impeller outlet and the secondary impeller inlet are close to each other, the pump efficiency decreases due to a vortex generated due to a sudden change in the flow direction. There is a problem of doing.

  Then, an object of this invention is to provide the pump apparatus and pump casing which can obtain high pump efficiency.

A pump device according to an aspect of the present invention houses a first impeller configured to be rotatable, a second impeller disposed on one side in an axial direction of the first impeller, and the first impeller. A cylindrical cavity that constitutes a housing space, a partition disposed in the cavity, a plurality of guide vanes disposed on an outer periphery of the first impeller on one axial side of the partition, and the partition A first intermediate casing comprising: a return vane disposed on the outer peripheral portion of the other main surface of the second vane; and a frustoconical guide wall disposed opposite to the inner peripheral side of the return vane and extending along the axial direction ; ,
A second intermediate casing that houses the second impeller;
Disposed between said first intermediate casing and the second intermediate casing, a flow path in communication with the inlet of the second impeller along the axial direction communicates with the outlet of the first impeller And a connection casing provided with a plurality of fins projecting from the peripheral wall portion toward the axial center of the flow path .

In the pump casing according to another aspect of the present invention, the number of the return blades is larger than the number of the guide blades.

  ADVANTAGE OF THE INVENTION According to this invention, the pump apparatus and pump casing which can obtain high pump efficiency can be provided.

Sectional drawing which shows the structure of the pump apparatus concerning 1st Embodiment. Explanatory drawing which shows the structure of the pump apparatus in a partial cross section. Explanatory drawing which expands and shows a part of FIG. Sectional drawing of the structure of the pump apparatus. Sectional drawing of the structure of the pump apparatus. Explanatory drawing which shows the relationship between the number of the fins of a pump apparatus, and a blade | wing. Explanatory drawing which shows the pump efficiency of the pump apparatus concerning each embodiment. Sectional drawing which shows the structure of the pump apparatus concerning 2nd Embodiment. Sectional drawing which shows the structure of the pump apparatus concerning 3rd Embodiment. Sectional drawing which shows the structure of the pump apparatus concerning the comparative example 1. FIG.

[First Embodiment]
Hereinafter, a pump device 10 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 7. FIG. 1 is a sectional view showing the configuration of the pump device according to the first embodiment, and FIGS. 2 and 3 are explanatory views showing a partially enlarged configuration of the pump device, omitting the rotating shaft 21. It shows. 4 and 5 are explanatory views showing the IV-IV section and the VV section of FIG. 1, respectively. FIG. 6 is an explanatory view showing the relationship among the number of blades of the impeller, guide blades, return blades and rectifying fins of the pump device, and FIG. 7 is an explanatory view showing pump efficiency of the pump device according to each embodiment.

  The pump apparatus 10 shown in FIG. 1 is applied to a water supply apparatus, for example. The pump device 10 is, for example, a multi-stage turbine pump that boosts water and supplies it to the secondary side, and its axial direction is provided along the vertical direction.

  The pump device 10 includes a motor 11 and a pump unit 12 connected to the shaft of the motor 11. The pump unit 12 includes a rotary shaft 21 protruding from the motor 11, a pump casing 22 constituting an outer shell, a first impeller 23 provided on the rotary shaft 21, a second impeller 24, a seal member 25, Is provided.

  As the rotating shaft 21, for example, a motor having the same main shaft length as that of a conventional three-stage turbine pump is used. By increasing the diameter of the impeller, the number of impellers is reduced by one at the same rotational speed.

  The pair of impellers 23 and 24 is a closed type impeller, and includes a pair of disk-shaped shrouds 26a and 26b and at least one blade 27 formed between the pair of shrouds 26a and 26b. . Inlets 23a and 24a are formed at the center of one shroud of each impeller 23 and 24, respectively. A pair of shrouds 26a, 26b of each impeller 23, 24 and a gap formed on the outer peripheral side of the blade 27 constitute an outlet 23b for discharging fluid. The blades 27 are curved and extend from the center side to the outer peripheral side with a predetermined curvature. The impellers 23 and 24 are rotatably accommodated in the intermediate casings 32 and 33. When the impellers 23 and 24 are rotated by driving the motor 11, fluid is sucked from the inflow ports 23a and 24a, and outward and peripheral from the outer outflow ports 23b and 24b. Drain the fluid in the direction.

  The pump casing 22 includes a suction casing 31, a pair of intermediate casings 32, a connection casing 34 that connects between the pair of intermediate casings 32, and a discharge casing 35.

  The suction casing 31 has a tubular suction portion 31a extending toward one end in the axial direction. The suction casing 31 forms a suction passage that communicates with the accommodation space and allows fluid to flow therethrough. The tip of the suction part 31a forms a circular suction port 31b. An attachment flange 31c is integrally formed at the tip of the suction portion 31a. A sleeve 31d facing the mouth portion of the impeller 23 is provided on the inner circumference of the flange 31c. The suction port 31b is formed to be connectable to piping or the like disposed on the primary side of the pump device 10.

  The first intermediate casing 32 includes a disk-shaped partition wall 32a, a cylindrical hollow portion 32b disposed on the outer peripheral edge of the partition wall 32a, a plurality of guide blades 32c, a plurality of return blades 32d, and a guide wall 32e. .

  The partition wall 32a has a disk shape having a shaft hole 32f through which the rotary shaft 21 passes. A plurality of guide vanes 32c are formed on the outer peripheral portion of one main surface of the partition wall 32a. The other main surface of the partition wall 32a is formed with a plurality of return blades 32d that are erected in the other axial direction. A frustoconical guide wall 32e is provided around the shaft hole 32f at the center of the partition wall 32a and on the inner peripheral side of the return blade 32d.

  The hollow portion 32b has a circular shape having an opening edge that is liquid-tightly fixed around the inlet 23a of the impeller 23, and is integrally provided with a cylindrical peripheral wall portion standing on the outer periphery.

  For example, four guide blades 32c are provided. For example, the guide blade 32c is erected in one axial direction at the outer peripheral portion on one main surface side of the partition wall 32a. The guide blade 32c is curved with a predetermined curvature from the center side toward the outer peripheral side.

  For example, eight return blades 32d are provided. For example, the return blade 32d is erected in the other axial direction on the other main surface side of the partition wall 32a. The return blade 32d is curved with a predetermined curvature from the center side toward the outer peripheral side. In the return blade 32d, four long return blades 32h and four short return blades 32i are alternately arranged in the circumferential direction. The four long return blades 32h are inside the outer end edge of the rectifying fin 34e in the radial direction, and from the same position as the opening edge of the central part of the cavity part 32b of the partition wall 32a, the peripheral wall part of the cavity part 32b It is formed to reach the inner wall. The four short return blades 32i are configured to be shorter than the long return blade 32h. One end of the short return blade 32i is located on the inner side of the outer edge of the rectifying fin 34e, and is located at the same position as the opening edge of the central portion of the cavity portion 32b of the partition wall 32a, and the other end is located on the cavity portion 32b. It is arranged at a predetermined position on the inner peripheral side with respect to the inner wall. The short return blade 32i divides the flow path formed between the pair of long return blades 32h into two.

  The position of the inner end of the return vane 32 d is arranged at the same position as the opening edge of the inlet of the connection casing 34.

  The guide wall 32e is configured integrally with the central portion of the partition wall 32a protruding toward the other end in the axial direction. The guide wall 32e is disposed around the shaft hole 32f at the center of the partition wall 32a, and is disposed to face the inner peripheral side of the return blade 32d. The guide wall 32e is configured in a truncated cone shape, and the outer surface of the guide wall 32e forms a curved surface that gently deflects in the axial direction from the other main surface of the partition wall 32a. The outer surface of the guide wall 32e guides the fluid flow in the axial direction with a gentle outer surface.

  In the intermediate casing 32, an accommodation space for accommodating the impeller 23 is formed on one axial side of the partition wall 32a. In the first intermediate casing, the outlet 23b of the impeller 23 reaches the outer peripheral portion along one main surface of the partition wall 32a and the guide blade 32c, passes through the flow hole 32g, and the other main surface and the return blade. A flow path is formed that extends along the line 32d to the inlet of the first connection casing 34 on the secondary side.

  The second intermediate casing 33 includes a disk-shaped partition wall 33a, a cylindrical hollow portion 33b disposed on the outer peripheral edge of the partition wall 33a, a plurality of guide blades 33c, a plurality of return blades 33d, and a guide wall 33e. . The second intermediate casing 33 is configured in the same manner as the first intermediate casing 32 except that the guide wall 33e is shorter than the guide wall 32e in the axial direction.

  The partition wall 33a has a disk shape having a shaft hole 33f through which the rotary shaft 21 passes. A plurality of guide vanes 33c erected in one axial direction are formed on the outer peripheral portion of one main surface of the partition wall 33a. A flow hole 33g penetrating in the axial direction is formed in the outer peripheral portion of the partition wall 33a. The other main surface of the partition wall 33a is formed with a plurality of return blades 33d that are erected in the other axial direction. A frustoconical guide wall 33e is provided around the shaft hole 33f at the center of the partition wall 33a and on the inner peripheral side of the return blade 33d.

The hollow portion 33b has a circular shape having an opening edge that is liquid-tightly fixed around the inlet 23a of the impeller 23, and is integrally provided with a cylindrical peripheral wall portion standing on the outer periphery.
For example, eight return blades 33d are provided and extend inward from the outer peripheral edge of the partition wall 33a.

  For example, four guide blades 33c are provided. For example, the guide vane 33c is erected in one axial direction at the outer peripheral portion on one main surface side of the partition wall 32a. The guide blade 33c is curved with a predetermined curvature from the center side toward the outer peripheral side.

  For example, eight return blades 33d are provided. For example, the return vane 33d is erected in the other axial direction on the other main surface side of the partition wall 33a. The return blade 33d is curved with a predetermined curvature from the center side toward the outer peripheral side. In the return blade 33d, four long return blades 33h and four short return blades 33i are alternately arranged in the circumferential direction. The four long return vanes 33h are radially inward of the outer edge of the rectifying fin 34e and from the same position as the opening edge at the center of the cavity 33b of the partition wall 33a, and the peripheral wall of the cavity 33b. It is formed to reach the inner wall. The four short return blades 33i are shorter than the long return blade 33h. One end of the short return blade 33i is located on the inner side of the outer edge of the rectifying fin 34e and is located at the same position as the opening edge of the central portion of the cavity 33b of the partition wall 33a, and the other end of the short return blade 33i. It is arranged at a predetermined position on the inner peripheral side with respect to the inner wall. The short return blade 33i divides the flow path formed between the pair of long return blades 33h into two.

  The positions of the inner ends of the plurality of return vanes 33 d are arranged at the same position as the opening edge of the inlet of the discharge casing 35.

  The guide wall 33e is integrally formed by raising the central portion of the partition wall 33a. The outer surface of the guide wall 33e forms a curved surface that gently deflects in the axial direction from the other main surface of the partition wall 33a. The guide wall 33e is configured to be shorter in the axial direction than the guide wall 32e, and the outer surface guides the fluid flow in the axial direction with a gentle outer surface.

  In the intermediate casing 33, an accommodation space for accommodating the impeller 23 is formed on one axial side of the partition wall 33a. In the second intermediate casing 33, the outlet 24b of the impeller 24 reaches the outer peripheral portion along one main surface of the partition wall 33a and the guide vane 33c, passes through the flow hole 33g, and returns to the other main surface and the return surface. A flow path is formed that extends along the blade 33d to the inlet of the discharge casing 35 on the secondary side.

  The connection casing 34 is disposed between the pair of intermediate casings 32 and 33 arranged in the axial direction. The connecting casing 34 is provided on the inner peripheral wall of one flange 34b, a tapered peripheral wall portion 34a whose secondary side is reduced in diameter in the axial direction, a pair of flanges 34b and 34c disposed at both ends in the axial direction, and the impeller 24. A sleeve 34d facing the mouse portion, and a plurality of rectifying fins 34e. The first connection casing 34 communicates with the outlet of the first impeller 23 and forms a flow path that communicates with the inlet of the second impeller 24.

  The plurality of rectifying fins 34e are projections having a predetermined thickness, projecting a predetermined height radially inward, and formed along the axial direction. The same number of the rectifying fins 34e as the return vanes 32d and 33d are provided, and in this embodiment, eight rectifying fins 34e are formed. It has a function as a baffle plate which guides the flow of the fluid flowing in the circumferential direction between the pair of intermediate casings 32 in the axial direction.

  The rectifying fins 34e have, for example, an integral structure in which a part of the inner surface of the connection casing 34 is raised, and are formed by casting when the peripheral wall portion 34a is manufactured. The rectifying fins 34e protrude radially inward from the inner wall of the peripheral wall portion 34a of the connection casing 34 and extend along the axial direction. The tip of the rectifying fin 34e on the other end side in the axial direction is located on one side in the axial direction with respect to the suction port of the impeller 24 on the secondary side. Specifically, for example, the rectifying fins 34e are arranged on one side of the inflow port 24a at a predetermined distance, for example, 5 mm or more.

  A flange 34 b at one end in the axial direction is connected to the opening of one intermediate casing 32. A sleeve 34d is provided on the inner peripheral edge of the flange 34c at the other end in the axial direction so as to face the outer periphery of the mouth portion of the other impeller 24. The outer peripheral portion of the flange 34 c is connected to the peripheral edge of the inflow port of the intermediate casing 33.

  For example, as shown in FIG. 10 as Comparative Example 1, the connecting casing 34 has an axial length of an intermediate casing disposed in the axial center of a three-stage pump device 100A in which three impellers are continuously arranged in the axial direction. It has the same length.

  As shown in FIG. 6, the impellers 23 and 24 have five blades 27, four guide blades 32c and 33c, eight return blades 32d and 33d, and eight rectifying fins 34e, which are set to have different numbers. Has been.

  The discharge casing 35 includes a cylindrical portion 35a and a discharge portion 35b formed continuously on a part of the peripheral wall of the cylindrical portion 35a. An opening communicating with the discharge portion 35b is formed on the inner peripheral surface of the cylindrical portion 35a. The discharge part 35b is a pipe extending outward from a part of the peripheral surface of the cylindrical part 35a, and forms a discharge path that communicates with the accommodation space and allows fluid to pass through. The tip of the discharge part 35b forms a circular discharge port 35c. An attachment flange 35d is integrally formed at the tip of the discharge portion 35b. The discharge port 35c is formed to be connectable to piping or the like disposed on the secondary side of the pump device 10.

  The pump device 10A is the same as the pump device 100A of Comparative Example 1 in the positional relationship between the pump suction port 31b and the discharge port 35c, and can be easily incorporated into a common water supply device. For example, the distance in the axial direction between the suction port 31b of the pump and the center of the discharge port 35c is set to L1.

  The casing cover 36 is connected to one end side of the cylindrical portion 35 a of the discharge casing 35. The casing cover 36 is formed with an opening through which the rotary shaft 21 passes.

  The seal member 25 is, for example, a mechanical seal. The seal member 25 is configured to be able to seal between the outer peripheral surface of the rotating shaft 21 and the opening of the casing cover 36.

  Next, the operation of the pump device 10 will be described with reference to FIG. In the pump device 10, when the rotor of the motor 11 rotates under the control of a control panel connected to the motor 11, the rotating shaft 21 rotates at a predetermined rotation speed. Accordingly, the plurality of impellers 23 and 24 attached to the rotating shaft 21 rotate at a predetermined rotation speed.

  As the impellers 23 and 24 rotate, fluid is sucked from the suction port 31 b of the pump casing 22. By the rotation of the first impeller 23, the fluid is sucked from the inlet 23a of the first impeller 23 and discharged from the outer outlet 23b. At this time, the fluid is discharged outward and circumferentially from the outlet 23b.

  The fluid discharged from the outlet 23b is guided by the intermediate casing 32 to the inlet 24a of the impeller 24 on the secondary side. Specifically, the fluid discharged from the outlet 23b of the impeller 23 is guided to the outer peripheral side of the partition wall 32a by the guide vane 32c on one main surface of the partition wall 32a, and passes through the circulation hole 32g to the other main surface. It is guided to the inner peripheral side by the return blade 32d on the other main surface. Further, the fluid is guided in the axial direction by the rectifying fins 34e of the connection casing 34, and is guided to the inlet 24a of the impeller 24 disposed on the secondary side.

  Similarly, the fluid sucked from the inlet 24a of the second impeller 24 by the rotation of the second impeller 24 is discharged from the outer outlet 24b and guided toward the outlet 35c, and passes through the outlet 35b. It is discharged outside.

According to the pump device 10 according to the present embodiment, the following effects can be obtained. That is, the connecting casing 34 is arranged between the intermediate casings 32 and 33, the axial distance between the primary and secondary impellers is provided, and the pressure loss is reduced by gradual change in the direction of water flow. it can. That is, since the water flow flowing into the inlet of the secondary impeller is bent at a right angle and directed in the axial direction after a certain time, the mutual collision of the plurality of jets is reduced, and the secondary inlet is reduced. By preventing the generation of vortices in the vicinity, pressure loss can be reduced. In addition, the connecting casing is tapered so that the cross-sectional area on the secondary side is reduced, and the flow from the discharge part of the intermediate casing on the primary side is changed little by little and guided in the axial direction. Since the change in flow becomes gradual compared to the above configuration, pressure loss can be reduced.
In addition, with the configuration in which the number of return blades 32d and 33d is set to be larger than the number of guide blades 32c and 33c, the fluid guided by the guide blades 32c and 33c passes through the U-shaped flow path and returns to the return blades 32d and 33d. By subdividing the fluid flowing through the return flow path by 33d, the rectifying effect is enhanced, the generation of local vortices in the flow path can be prevented, and the pressure loss can be reduced. Furthermore, by setting the number of return blades 32d and 33d to be a multiple of the guide blades 32c and 33c, the water flow flowing out from the guide blades 32c and 33c is prevented from colliding with the tips of the long return blades 32h and 33h. By rectifying with the return vanes 32i and 33i, the effect of enhancing the rectification effect is obtained.

  Further, by increasing the number of guide blades 32c and 33c as compared with the number of blades 27 of the impellers 23 and 24, it is possible to prevent the jets flowing out from the impellers 23 and 24 from colliding with the tips of the guide blades 32c and 33c at the same time. be able to. If the number of guide vanes is larger than the number of impellers, the flow loss increases due to the reduction of the flow path cross-sectional area due to the rectifying effect of the guide vanes, and the pressure loss increases. The pressure loss can be suppressed by increasing the number of blades 32c and 33c.

  The positions of the inner ends of the plurality of return vanes 33 d are arranged at the same position as the opening edge of the inflow port of the discharge casing 35. The position of the inner end of the return vane 32 d is arranged at the same position as the opening edge of the inlet of the connection casing 34. Therefore, the suction flow collides with the end face of the flow path on the inflow side of the connection casing 34 and the discharge casing 35 by making the inner diameter of the return vanes 33d and 32d of the return flow path the same as the flow path diameter on the secondary side. Can be prevented, and a decrease in pump efficiency can be prevented.

  Further, in the above embodiment, the guide wall is formed by extending the main outflow portion of the return passage of the first intermediate casing around the central outflow portion toward the connection casing, so that the return passage on the other end side of the partition wall 32a. It is possible to prevent the fluid flowing from the outer periphery to the center from colliding with the main shaft and causing power loss.

  Furthermore, in the above embodiment, the number of rectifying fins 34e is the same as the number of return vanes 32d of the return flow path, and the number of flow paths flowing from the outer periphery of the return flow path toward the central portion and the flow path of the suction casing are passed. By matching the number of flow paths to be made, the change in the water flow can be reduced and the pressure loss can be suppressed.

  Further, by arranging the tip of the rectifying fin 34e on one side in the axial direction from the suction port of the secondary impeller 24, the number of rectifying fins 34e and the number of blades 27 of the impeller 24 are different, so that the flow Disturbance can be prevented.

  FIG. 7 is a graph showing the relationship between the flow rate, pump efficiency, shaft power, and total head of the pump device 10 according to this embodiment and the pump device 100A according to the comparative example. In FIG. 7, the horizontal axis represents the flow rate (L / min), and the vertical axis represents the total head (m), pump efficiency (%), and shaft power / 100 (W). The pump device 100A includes a three-stage impeller, and includes three intermediate casings that accommodate the respective impellers continuously in the axial direction without using a connection casing. The axial distance L1 between the suction port 31b and the discharge port 35c of the pump device 100A is the same as that of the pump device 10. As shown in FIG. 7, the pump device 10 according to the present embodiment has a maximum pump efficiency of about 10% higher than that of the pump device 100A that is a three-stage turbine pump shown in Comparative Example 1, and the maximum shaft power is increased. After the reduction of 230 W, the total head exceeds the flow rate of 250 L / min or more, and the performance is improved.

[Second Embodiment]
Hereinafter, a pump device 10A according to a second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a side view of the pump device 10A according to the second embodiment with a partial cross section.

  The pump apparatus 10A according to the second embodiment is the same as that of the first embodiment except that a three-stage structure is used. Therefore, the overlapping description is omitted.

  As shown in FIG. 8, the pump device 10 </ b> A includes three impellers 23, 23, and 24 and three intermediate casings 32, 32, and 33 that accommodate the impellers 23, 23, and 24, respectively. Between the three intermediate casings 32, 32, 33, connection casings 34, 34 are provided, respectively. Other configurations are the same as those of the pump device 10 according to the first embodiment.

  In this embodiment, each impeller 23, the intermediate casing 32, and the connection casing 34 are impellers 23. The intermediate casing 32 and the connection casing 34 are configured similarly. Also in this embodiment, the same effect as the first embodiment can be obtained.

[Third Embodiment]
Hereinafter, a pump device 10B according to a third embodiment of the present invention will be described with reference to FIG. FIG. 10 is a side view showing a partial cross section of a pump device 10B according to the third embodiment.

  The pump device 10B according to the third embodiment is a single-stage turbine pump, and includes an impeller 23, a suction casing 31A, an intermediate casing 32 that houses the impeller 23, and a discharge casing 35. The intermediate casing 32 and the discharge casing 35 are configured similarly to the intermediate casing 32 and the discharge casing 35 according to the first embodiment.

  In this embodiment, the rotating shaft 21 is set to the same length as the main shaft length of the conventional two-stage turbine pump. Moreover, 31 A of suction casings are the structures by which the suction inlet 31b and the discharge outlet 35c are distribute | arranged by the same positional relationship as the suction inlet 31b and the discharge outlet 35c of 1st Embodiment, for example. For example, the axial distance between the suction port 31b and the discharge port 35c is set to L1. Therefore, the same motor as the other two-stage pump device is used, and the same discharge pipe or the like can be applied. Therefore, a highly versatile pump configuration can be obtained.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. For example, in the above-described embodiment, the multi-stage land pump on the vertical axis is used, but the multi-stage land pump on the horizontal axis may be used, or a multi-stage submersible pump or a deep well multi-stage submersible pump installed in a receiving tank for storing tap water. . Also in this case, the same effects as those of the above embodiments can be obtained.

In addition, each component illustrated in the above embodiment may be deleted, and the shape, structure, material, and the like of each component may be changed. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[1]
A first impeller configured to be rotatable;
A second impeller disposed on one of the axial directions of the first impeller;
A first intermediate casing that houses the first impeller;
A second intermediate casing that houses the second impeller;
A connecting casing that is disposed between the first intermediate casing and the second intermediate casing and that communicates with the outlet of the first impeller and forms a flow path that communicates with the inlet of the second impeller; A pump device.
[2]
The connection casing includes a peripheral wall portion that forms a tapered flow path along the axial direction and in which a cross-sectional area on the secondary side decreases.
One end in the axial direction is connected to the opening of one of the intermediate casings,
[1] comprising a sleeve having the other axial end connected to the opening of the other intermediate casing and opposed to the outer periphery of the mouth portion disposed at the periphery of the inlet of the impeller in the intermediate casing The pump device described.
[3]
The connection casing includes a plurality of fins protruding inwardly,
The intermediate casing includes a cylindrical hollow portion that forms a housing space for housing the impeller, a partition wall disposed in the hollow portion, and a plurality of guides disposed on an outer periphery of the impeller on one axial side of the partition wall. A blade, a return blade disposed on the outer peripheral portion of the main surface on the other side of the partition wall, and a frustoconical guide wall that is disposed opposite to the inner periphery of the return blade and extends along the axial direction. The pump device according to [1] or [2].
[4]
The pump device according to [3], wherein the number of return blades is greater than the number of guide blades.
[5]
A suction casing having a suction port and constituting a flow path communicating with the inlet of the primary impeller; and
A pump device according to any one of [1] to [4], further comprising: a discharge casing having a discharge port and forming a flow path communicating with an outlet of the secondary side impeller.
[6]
A plurality of intermediate casings each housing a plurality of impellers;
A connection comprising a plurality of rectifying fins that are arranged between a plurality of the intermediate casings and that communicate with the outlet of the primary impeller and the inlet of the secondary impeller and project inwardly A pump casing comprising a casing.

DESCRIPTION OF SYMBOLS 10, 10A, 10B ... Pump apparatus, 11 ... Motor, 12 ... Pump part, 21 ... Rotary shaft, 22 ... Pump casing, 23 ... Impeller, 23a ... Inlet, 23b ... Outlet,
24 ... Impeller, 24a ... Inlet, 24b ... Outlet, 25 ... Seal member, 26a ... Shroud, 26b ... Shroud, 27 ... Blade, 31 ... Suction casing, 31a ... Suction part, 31b ... Suction port, 31c ... Flange, 32 ... Intermediate casing, 32a ... Partition, 32b ... Cavity, 32c ... Guide vane, 32d ... Return vane, 32e ... Guide wall, 32f ... Shaft hole, 32g ... Distribution hole, 32h ... Long return vane, 32i ... Short return vane 33 ... Intermediate casing, 33a ... Partition, 33b ... Cavity, 33c ... Guide vane, 33d ... Return vane, 33e ... Guide wall, 33f ... Shaft hole, 33g ... Distribution hole, 33h ... Long return vane, 33i ... Short return Blades 34... Connection casing 34 a. Circumferential wall 34 b and 34 c Flange 34 d Sleeve 34 e Flow fin 35 35 Discharge casing 35 ... cylindrical portion, 35b ... discharge unit, 35c ... discharge port, 35d ... flange, 36 ... casing cover, 100A ... pumping device, 31A ... suction casing.

Claims (2)

A first impeller configured to be rotatable;
A second impeller disposed on one of the axial directions of the first impeller;
A cylindrical hollow portion constituting a housing space for housing the first impeller, a partition wall disposed in the cavity portion, and a plurality of portions disposed on the outer periphery of the first impeller on one axial side of the partition wall Guide blades, a return blade disposed on the outer peripheral portion of the other main surface of the partition wall, and a truncated cone-shaped guide wall that is disposed opposite to the inner peripheral side of the return blade and extends in the axial direction. a first intermediate casing comprising,
A second intermediate casing that houses the second impeller;
Disposed between said first intermediate casing and the second intermediate casing, a flow path in communication with the inlet of the second impeller along the axial direction communicates with the outlet of the first impeller A connecting casing comprising: a peripheral wall portion that forms a plurality of fins that protrude from the peripheral wall portion toward the axial center of the flow path;
A pump device comprising: The pump device according to claim 1 , wherein the number of the return blades is larger than the number of the guide blades.