Motor pump

Abstract

To provide a motor pump having means for surely cooling an entire motor part including an opposite load-side bearing.SOLUTION: A motor pump includes: a main impeller; a pump casing; a main shaft; an opposite load-side bearing rotationally supporting the main shaft; an opposite load-side bearing bracket for holding the opposite load-side bearing; a motor frame for storing a rotor and a stator that rotate integrally with the main shaft; a cooling jacket forming an annular space for receiving a cooling liquid between the motor frame and itself; an intermediate casing for forming a flow path of the cooling liquid from at least one first opening to at least one second opening; and a circulation impeller provided on the main shaft in the flow path. The opposite load-side bearing bracket is attached to a motor frame to have a surface partially exposed to the annular space, and includes an upper end and lower end positioned above the exposed surface of the opposite load-side bearing bracket. A lower end of a tubular member is disposed to open in the flow path via the second opening of the intermediate casing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a motor pump, and more particularly to a motor pump for use underwater. [Background technology]

[0002] Submersible motor pumps are generally used to transport sewage, gray water, and other wastewater. For example, sewage generated in the basement of a building is temporarily stored in a drainage tank (pit) installed further below via an inlet pipe. When the water level in the pit reaches a predetermined start-up level, the submersible pump installed in the pit starts up. The sewage is pumped up into a sewage manhole by the submersible pump, and is then drained into the public sewer pipes via the manhole. In submersible pumps, the motor is generally installed above the impeller, so when the water level in the pit drops, the motor is exposed to the air. To prevent temperature increases due to heat generated by the motor, submersible pumps have a predetermined stop water level, and the operation of the submersible pump stops when the stop water level is reached.

[0003] However, to prevent the problem of sewage odor, it is preferable to pump the sewage as close to the bottom of the pit as possible. From this perspective, a jacket is provided around the motor, and the motor is cooled by circulating liquid within the jacket. In such a coolant circulation system, a circulation impeller for circulating the coolant is used separately from the main impeller for transporting sewage, etc. Patent Document 1 describes a coolant circulation structure for a pump using a circulation impeller.

[0004] Patent document 2 also describes a circulation flow path in which cooling liquid is supplied into a cooling jacket covering the motor part of an underwater motor pump by the rotation of a circulation impeller, and is returned to the pump bracket through a tubular member due to the large pressure difference between the upper and lower spaces separated by a partition member.

[0005] However, with the configurations described in Patent Documents 1 and 2, it is difficult to sufficiently cool the non-load side bearing during air operation when the motor section is exposed to air. The non-load side bearing is a bearing that is located above the motor section and supports the rotating shaft connected to the main impeller.

[0006] The non-load side bearing, located above the motor section, is exposed to air during air operation. The non-load side bearing can generate heat due to various factors. One possible cause of heat generation in the non-load side bearing is heat generated by the bearing itself due to sliding. Another possible cause is heat transfer from the stator and rotor sections of the motor section to the non-load side bearing. Therefore, there is a need for a means to reliably cool the entire motor section, including the non-load side bearing. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-57551 [Patent Document 2] Japanese Patent Application Publication No. 2018-059497 Summary of the Invention [Problem to be solved by the invention]

[0008] According to one embodiment of the present invention, it is possible to provide a submersible motor pump that can reliably cool the entire motor section, including the non-load side bearing. [Means for solving the problem]

[0009] According to one embodiment of the present invention, there is provided a motor pump including a main impeller configured to transport water by rotation, a pump casing that houses the main impeller, a main shaft connected to the main impeller, a non-load-side bearing that rotatably supports the main shaft on the non-load side, a non-load-side bearing bracket that holds the non-load-side bearing, a motor frame that houses a rotor that rotates integrally with the main shaft and a stator that is disposed on the outer periphery of the rotor, a cooling jacket that surrounds the outer periphery of the motor frame and defines an annular space for receiving coolant between the motor frame and the cooling jacket, an intermediate casing that is disposed between the pump casing and the motor frame and defines a coolant flow path from at least one first opening to at least one second opening, and a circulation impeller attached to the main shaft within the flow path. The non-load-side bearing bracket is attached to the motor frame with a surface partially exposed within the annular space. The motor pump further includes at least one tubular member that is disposed in the annular space and has an upper end located above the exposed surface of the non-load-side bearing bracket and a lower end. The lower end of the tubular member is positioned to open into the flow passage through the second opening in the intermediate casing. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a vertical cross-sectional view of a motor pump according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a partially enlarged view of FIG. 1, illustrating the flow path in the intermediate casing. [Figure 3] FIG. [Figure 4] FIG. 2 is a longitudinal cross-sectional view of the tubular member of the first embodiment. [Figure 5] FIG. 10 is a top view of the intermediate casing, showing the arrangement of the tubular members. [Figure 6] 10A and 10B are diagrams illustrating a method for fixing a tubular member. [Figure 7] FIG. 5 is a vertical cross-sectional view of a motor pump according to a second embodiment of the present invention. [Figure 8] FIG. 10 is a cross-sectional view of a non-load side bearing bracket in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. Note that the following description merely shows an example, and is not intended to limit the technical scope of the present invention to the following embodiments. Furthermore, in the drawings, identical or corresponding components are designated by the same reference numerals, and redundant description will be omitted. Furthermore, in the following description, terms indicating directions such as "upper" and "lower" are used to describe the installation state of the motor pump of each embodiment shown in FIG. 1, etc. In other words, "upper" means the side farther from the main impeller, and "lower" means the side closer to the main impeller.

[0012] [First embodiment] A first embodiment of the present invention will be described below with reference to Figs. 1 to 6. Fig. 1 is a longitudinal sectional view of a motor pump according to the first embodiment. Fig. 2 is a partially enlarged view of Fig. 1. Fig. 3 is a top view of an inner casing. Fig. 4 is a longitudinal sectional view of a tubular member. Fig. 5 is a top view of an intermediate casing. Fig. 6 is a view for explaining a method of fixing the tubular member.

[0013] The motor pump 10 of the first embodiment is used as a sewage pump for transporting liquids containing impurities and filth, such as sewage, wastewater, or river water (collectively referred to as "water" in this embodiment). As shown in the figure, the motor pump 10 includes a pump portion 20 and a motor portion 30.

[0014] The pump section 20 includes a main impeller 21 that rotates about a vertical axis AL, and a pump casing 22 that houses the main impeller 21. The main impeller 21 is connected to a main shaft 31 of the motor section 30, and rotates as the main shaft 31 rotates. The pump casing 22 has a suction port 22a and a discharge port 22b, and defines a water flow path together with an intermediate casing 23 (specifically, the bottom of the intermediate casing 23), which will be described later.

[0015] The intermediate casing 23 is disposed between the pump section 20 and the motor section 30 in a position covering the back side (upper side in FIG. 1 ) of the main impeller 21. In this embodiment, the bottom of the intermediate casing 23 is formed by a side plate 23b that is separate from the main body 23a of the intermediate casing 23. The side plate 23b is attached to the main body 23a of the intermediate casing 23 with screws or the like. However, in other embodiments, the main body 23a of the intermediate casing 23 and the side plate 23b may be integrally formed with each other. In the pump section 20, water is transferred from the suction port 22a to the discharge port 22b as the main impeller 21 rotates.

[0016] The intermediate casing 23 may be fixed to the pump casing 22 with screws or the like. The intermediate casing 23 is preferably made of a material with high thermal conductivity, such as an aluminum alloy or a copper alloy. A through-hole (reference numeral omitted) is formed in the intermediate casing 23, through which the main shaft 31 of the motor section 30 is inserted. Furthermore, mechanical seals 25, 39 for sealing the main shaft 31 are provided in this through-hole.

[0017] The motor section 30 provides a rotational driving force to the main impeller 21. The motor section 30 includes a main shaft 31 that rotates about an axis AL, a rotor 32 that rotates integrally with the main shaft 31, and a stator 33 that is provided on the outer periphery of the rotor 32. In this embodiment, the motor section 30 is configured as an induction motor, and the rotor 32 has a rotor core 321 and a secondary conductor 322, but other types such as a synchronous motor may also be used. The stator 33 has a stator core 331 and a stator coil 332 wound around the stator core 331. A power line is connected to the stator coil 332, and power is supplied from an external power source (e.g., a commercial power source) via a cable 43.

[0018] The motor section 30 further includes a motor frame 34. In this embodiment, the motor frame 34 includes a cylindrical motor frame main body 34a and an upper cover 34b disposed on the upper portion of the motor frame main body 34a. However, the specific shape of the motor frame 34 is not limited to that shown in the figure. In this embodiment, a stator core 331 is fixed to the inner peripheral surface of the cylindrical motor frame main body 34a of the motor frame 34. The upper cover 34b includes an opening (reference numeral omitted) through which the cable 43 is passed. The motor frame 34 may be formed of stainless steel, or a resin such as polypropylene resin (PP resin), polyphenylene sulfide resin (PPS resin), or polyamide resin, or a metal such as an aluminum alloy or copper alloy. Hereinafter, the pump section 20 side of the motor section 30 (lower side in FIG. 1) will be referred to as the "load side," and the opposite side (upper side in FIG. 1) will be referred to as the "anti-load side." A load-side bearing bracket 37 is fixed to the lower end of the motor frame main body 34a. The load side bearing bracket 37 holds a load side bearing 38 for supporting the main shaft 31 of the motor section 30 .

[0019] A non-load side bearing bracket 40 can be disposed between the motor frame main body 34a and the upper cover 34b. The non-load side bearing bracket 40 holds a non-load side bearing 41 for supporting the main shaft 31 of the motor section 30. In this embodiment, the outer peripheral end of the non-load side bearing bracket 40 is sandwiched between the motor frame main body 34a and the upper cover 34b. The non-load side bearing bracket 40 is hermetically fixed to the inner surfaces of the motor frame main body 34a and the upper cover 34b via fixing parts 40-1. This configuration improves the water resistance of the motor pump 10, achieving water resistance of, for example, about IP68 (JIS C 0920).

[0020] A cylindrical cooling jacket 57 is disposed so as to surround the outer peripheral surface of the motor frame 34 of the motor section 30. As a result, an annular space 59 for receiving the coolant 27 is formed between the motor frame 34 and the cooling jacket 57. As shown in FIG. 1, the non-load side bearing bracket 40 is disposed within the annular space 59 between the motor frame main body 34a and the upper cover 34b. The cooling jacket 57 has a surface (in this embodiment, the outer peripheral end surface 42) that is exposed to the outside. The cooling jacket 57 is arranged so that the upper end of the annular space 59 is located above the outer peripheral end surface 42 of the non-load side bearing bracket 40. The opening at the upper end of the cooling jacket 57 is closed by the non-load side jacket side plate 56. Note that in this embodiment, the non-load side jacket side plate 56 is configured as a member separate from the cooling jacket 57. However, in other embodiments, the non-load side jacket side plate 56 may be formed integrally with the cooling jacket 57.

[0021] The annular space 59 between the inner circumferential surface of the cooling jacket 57 and the outer circumferential surface of the motor frame 34 is filled with the coolant 27, leaving an air layer 70 at the top. The coolant 27 is used to cool the heat generated in the motor portion 30. The coolant 27 may be, for example, an antifreeze solution such as a propylene glycol solution or an ethylene glycol solution. The air layer 70 may be provided to absorb volume changes in the coolant 27 caused by temperature changes. However, depending on the pressure resistance of the cooling jacket 57, etc., the air layer 70 may not necessarily be provided. The lower end of the cooling jacket 57 may be attached to the intermediate casing 23.

[0022] The motor pump 10 has an intermediate casing 23 disposed between the pump section 20 and the motor section 30, which defines a flow path 24 capable of receiving the flow of coolant 27 within an annular space 59. A circulation impeller 60 disposed within the flow path 24 of the intermediate casing 23 generates the flow of coolant 27. FIG. 1 shows openings 371 and 373 formed in the upper surface 23a-1 of the intermediate casing 23. A tubular member 58, described below, is disposed within the opening 371. The coolant 27 within the annular space 59 can flow from the opening 373 of the intermediate casing 23 through the flow path 24 and into the suction port 60a (see FIG. 2) of the circulation impeller 60. The coolant 27 from the discharge port 60b (see FIG. 2) of the circulation impeller 60 can flow through the flow path 24 and into the tubular member 58 via the opening 371. In this embodiment, the openings 371, 373 are formed in the upper surface 23a-1 of the intermediate casing 23 (specifically, the main body 23a) so as to face the annular space 59. Therefore, the upper surface 23a-1 of the intermediate casing 23 extends laterally (in other words, radially outward) beyond the motor frame 34. However, in other embodiments, the openings 371, 373 may be in any positions as long as they are capable of communicating with the annular space 59. For example, the openings 371, 373 may be formed in a side wall of the intermediate casing 23.

[0023] FIG. 2 is a partially enlarged view of FIG. 1 showing the configuration of the flow path 24 of the intermediate casing 23. In this embodiment, the flow path 24 of the intermediate casing 23 is separated into a suction flow path 24a and a discharge flow path 24b by an inner casing 26 disposed within the intermediate casing 23. FIG. 3 shows a top view of the inner casing 26. The inner casing 26 may be disposed so as to partially contact the inner wall of the intermediate casing 23, for example, at position 26-1 in FIG. 3, to prevent leakage of the coolant 27 from the discharge flow path 24b (high-pressure side) to the suction flow path 24a (low-pressure side). The inner casing 26 may be fixed to the intermediate casing 23 with screws or the like. The provision of the inner casing 26 increases the flow velocity of the coolant 27 in the flow path 24 (particularly the discharge flow path 24b), thereby improving the efficiency of heat exchange between the water in the pump casing 22 and the coolant 27.

[0024] The suction flow passage 24a and the discharge flow passage 24b of the intermediate casing 23 are filled with coolant 27. The circulation impeller 60 is attached to the main shaft 31 between the mechanical seals 25, 39. The circulation impeller 60 rotates integrally with the main shaft 31. As shown by the arrows in FIG. 2 , as the circulation impeller 60 rotates, the coolant 27 in the annular space 59 of the cooling jacket 57 is sucked into the suction port 60a of the circulation impeller 60 from the opening 373 of the intermediate casing 23 through the suction flow passage 24a. Meanwhile, the coolant 27 discharged from the discharge port 60b of the circulation impeller 60 passes through the discharge flow passage 24b of the intermediate casing 23 and is discharged into the tubular member 58 arranged in the opening 371.

[0025] In this embodiment, the circulation impeller 60 is a centrifugal impeller. However, in other embodiments, the circulation impeller 60 does not have to be a centrifugal impeller, and may be, for example, an axial flow impeller.

[0026] 1, the tubular member 58 extends longitudinally along the outer circumferential surface of the motor frame 34 within the annular space 59 of the cooling jacket 57. A lower end 58-2 of the tubular member 58 is disposed in the opening 371 of the intermediate casing 23. However, in other embodiments, the tubular member 58 may extend beyond the opening 371 into the discharge flow passage 24b. In this embodiment, it is sufficient that the lower end 58-2 of the tubular member 58 opens into the discharge flow passage 24b.

[0027] Thus, the tubular member 58 is connected to the flow path 24 of the intermediate casing 23 and extends within the annular space 59. The tubular member 58 extends to a position above the outer peripheral end surface 42 of the non-load side bearing bracket 40. Therefore, the tubular member 58 has an upper end 58-1 that is located at a position above the outer peripheral end surface 42 of the non-load side bearing bracket 40.

[0028] FIG. 4 is a partially enlarged view of FIG. 1 , showing the upper portion of the tubular member 58. In FIG. 4 , the shape of a flow path 580 defined by the inner circumferential surface of the tubular member 58 is indicated by a dashed line. As shown in FIG. 4 , the flow path 580 may include a lower flow path 581 extending from the lower end 58-2 of the tubular member 58 with a substantially constant diameter, and an upper flow path 582 extending upward from the lower flow path 581. The upper flow path 582 includes a tapered section 582-1 that tapers to a reduced diameter, and a small-diameter section 582-2 adjacent to the tapered section 582-1. The small-diameter section 582-2 can maintain the diameter of the tip of the tapered section 582-1 (i.e., the diameter after the diameter is reduced). The small-diameter section 582-2 has a substantially constant diameter smaller than the diameter of the lower flow path 581 and extends a predetermined distance from the tip of the tapered section 582-1. The upper flow passage 582 of the tubular member 58 forms a throttled portion of the tubular member 58. The throttled portion can increase the flow rate of the coolant 27 that flows in from the lower end 58-2 of the tubular member 58. However, as long as the upper end 58-1 of the tubular member 58 is positioned above the outer peripheral end surface 42 of the non-load side bearing bracket 40, the upper flow passage 582 of the tubular member 58 may have only the tapered portion 582-1. Alternatively, the upper flow passage 582 may have only the small-diameter portion 582-2.

[0029] FIG. 5 is a top view of the intermediate casing 23, illustrating the arrangement of the tubular member 58 (specifically, the lower end 58-2) relative to the intermediate casing 23. FIG. 5 also illustrates the cooling jacket 57. As shown in FIG. 5, in the motor pump 10 of this embodiment, the intermediate casing 23 has two openings 371 and 372 and two openings 373 and 374. The tubular members 58 are arranged in the openings 371 and 372. Therefore, in this embodiment, the intermediate casing 23 is configured to form a flow path 24 for the coolant 27 from the openings 373 and 374 to the openings 371 and 372. The openings 373 and 374 are inlet openings for the coolant 27 from the annular space 59 to the flow path 24 of the intermediate casing 23, and are also referred to as first openings. In contrast, the openings 371 and 372 are outlet openings for the coolant 27 from the flow path 24 of the intermediate casing 23 to the tubular member 58, and are also referred to as second openings.

[0030] As shown in FIG. 5 , for example, the first openings 373 and 374 are located on opposite sides of the intermediate casing 23 in the diametric direction, and the second openings 371 and 372 are also located on opposite sides of the intermediate casing 23 in the diametric direction. On the upper surface of the intermediate casing 23, the openings 371, 372, 373, and 374 are arranged at equal intervals in the circumferential direction. However, the number and arrangement of the first openings and second openings are not particularly limited. The second openings are formed according to the number and arrangement of the tubular members 58, and may be formed as circular holes having a diameter substantially equal to the outer diameter of the tubular members 58 at which they are arranged. The first openings have a length extending in the circumferential direction of the intermediate casing 23, and the specific dimensions are not particularly limited. In this embodiment, The intermediate casing 23 may be provided with at least one first opening and at least one second opening.

[0031] FIG. 6 shows an example of a method for fixing the tubular member 58. The tubular member 58 may be fixed to, for example, the motor frame 34. In the example of FIG. 6, the tubular member 58 may be fixed by fastening to the motor frame 34 (in this embodiment, the motor frame main body 34a). For example, as shown in FIG. 6, a convex portion 34a-1 that protrudes radially outward may be formed on the outer peripheral surface of the motor frame main body 34a, and a bracket 584 that covers the outer peripheral surface of the tubular member 58 may be fixed to the convex portion 34a-1 with screws or the like. As shown in FIG. 1, in the motor pump 10 of this embodiment, the tubular member 58 is fixed to the upper convex portion 34a-1 and the lower convex portion 34a-2 of the motor frame 34. The tubular member 58 may be fixed to the upper convex portion 34a-1 and the lower convex portion 34a-2 using the same fixing method. However, the specific position and fixing method for the tubular member 58 are not particularly limited. For example, the tubular member 58 may be secured at the openings 371 , 372 in the intermediate casing 23 .

[0032] As described above, in this embodiment, the upper flow path 582 of the tubular member 58 constitutes the throttle portion of the tubular member 58. The throttle portion can increase the flow rate of the coolant 27 that flows in from the lower end 58-2 of the tubular member 58. This allows the coolant 27 to be ejected from the upper end 58-1 of the tubular member 58 at a high flow rate.

[0033] Furthermore, the tubular member 58 extends within the annular space 59 to a position above the outer peripheral end surface 42 of the non-load side bearing bracket 40. In other words, the outer peripheral end surface 42 of the non-load side bearing bracket 40 is exposed within the annular space 59 at a position lower than the upper end 58-1 of the tubular member 58. Therefore, the coolant 27 ejected from the upper end 58-1 of the tubular member 58 is reliably brought into contact with the outer peripheral end surface 42 of the non-load side bearing bracket 40, thereby cooling the non-load side bearing bracket 40 (and therefore the non-load side bearing 41) via the outer peripheral end surface 42. The throttled portion ensures that the ejected coolant 27 has a high flow velocity. Therefore, efficient heat exchange is possible between the coolant 27 and the non-load side bearing bracket 40 (and therefore the non-load side bearing 41).

[0034] As described above, the volume of the coolant 27 changes due to temperature changes and other factors. The level of the coolant 27 in the cooling jacket 57 may also decrease over time. For example, if an aqueous solution such as a propylene glycol solution is used as the coolant 27, the water content of the coolant 27 may react with cast iron, a common material used in the wetted parts of the motor pump 10, generating gases such as hydrogen gas. The resulting reactive gases cause the coolant 27 to lose water, lowering the level of the coolant 27. Furthermore, deterioration of components such as the mechanical seals 25 and 39 may cause the coolant 27 to leak, lowering the level of the coolant 27. In this case, during air operation of the motor pump 10, a portion of the upper part of the motor frame 34 may not be surrounded by the coolant 27.

[0035] In this embodiment, within the annular space 59, the upper end 58-1 of the tubular member 58 is located above the non-load side bearing bracket 40, which is located at the top of the motor portion 30. Therefore, even if the liquid level of the coolant 27 drops, the upper part of the motor portion 30 that is not surrounded by the coolant 27 can be cooled by spraying the coolant 27 at a position higher than the liquid level of the coolant 27.

[0036] If the upper end 58-1 of the tubular member 58 is not positioned above the outer peripheral end surface 42 of the non-load side bearing bracket 40, it is possible to make the coolant 27 reach the outer peripheral end surface 42 of the non-load side bearing bracket 40 and cool the non-load side bearing bracket 40 by adjusting the flow rate, etc. However, in this embodiment, the upper end 58-1 of the tubular member 58 is positioned above the outer peripheral end surface 42 of the non-load side bearing bracket 40, so that the coolant 27 can be reliably brought into contact with the outer peripheral end surface 42.

[0037] As described above, the intermediate casing 23, together with the pump casing 22, defines the flow path of water transported by the main impeller 21. Therefore, the intermediate casing 23, particularly the side plate 23b forming the bottom of the intermediate casing 23, is constantly cooled by water, and the coolant 27 is cooled by water through the intermediate casing 23. The coolant 27, which has reached a high temperature through heat exchange, is drawn into the suction port 60a of the circulation impeller 60 by the centrifugal force of the circulation impeller 60 from the cooling jacket 57 through the suction flow path 24a between the intermediate casing 23 and the inner casing 26, and then discharged from the discharge port 60b into the discharge flow path 24b. The discharged coolant 27 is cooled in the discharge flow path 24b between the inner casing 26 and the side plate 23b and flows into the tubular member 58 through the openings 371 and 372. The flow velocity of the coolant 27 is increased by the effect of the throttle portion at the top of the tubular member 58. Therefore, the cooling liquid 27 is ejected from the upper end 58-1 of the tubular member 58 at a high flow rate.

[0038] The ejected coolant 27 comes into contact with the outer peripheral end surface 42 of the counter-load side bearing bracket 40 and cools the counter-load side bearing bracket 40 via the outer peripheral end surface 42. The ejected coolant 27 also comes into contact with the motor frame 34 and exchanges heat with the stator coil 332 via the motor frame 34, thereby cooling the stator coil 332. The coolant 27 itself expands when heated, but this change in volume due to the expansion of the coolant 27 can be absorbed by the air layer 70. Outside the tubular member 58, a return flow path for the coolant 27 is formed, running from the cooling jacket 57 through the openings 373 and 374 of the intermediate casing 23 and the suction flow path 24a to the suction port 60a. In this way, the coolant 27 circulates within the motor pump 10.

[0039] Thus, according to the first embodiment, the cooling jacket 57, the circulation impeller 60, the intermediate casing 23, and the tubular member 58 form a cooling mechanism for cooling the motor section 30. This makes it possible to provide a motor pump 10 that can be operated in air. Unlike the prior art, a simple method can be used to reliably bring the coolant 27 into contact with the non-load side bearing bracket 40 and perform heat exchange. Furthermore, since the tubular member 58 includes a throttle portion, the flow rate of the coolant 27 is increased, allowing for efficient heat exchange. This improves the cooling effect of the entire motor section 30, including the non-load side bearing bracket 40.

[0040] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to FIGS. 7 and 8. In the motor pump 10 of the first embodiment shown in FIG. 1, the tubular member 58 is configured as a throttle pipe having a throttle portion. In the second embodiment, a tubular member 58A is provided instead of the tubular member 58 of the first embodiment. Furthermore, the non-load side bearing bracket 40 includes an extension portion 44 that extends radially outward beyond the motor frame 34. The tubular member 58A is positioned so as to contact the extension portion 44. FIG. 7 is a longitudinal sectional view of a motor pump 10A according to the second embodiment. FIG. 8 is a transverse sectional view of the non-load side bearing bracket 40 of the second embodiment. In the following description of the second embodiment, differences from the first embodiment will be mainly described, and detailed description of other configurations will be omitted.

[0041] 7, the motor pump 10A includes a tubular member 58A that is disposed within the annular space 59 of the cooling jacket 57. The tubular member 58A extends vertically within the annular space 59 of the cooling jacket 57 along the outer circumferential surface of the motor frame 34. A lower end 58A-2 of the tubular member 58A is disposed in the opening 371 of the intermediate casing 23. However, it is sufficient that the lower end 58A-2 of the tubular member 58A opens into the discharge flow path 24b of the intermediate casing 23.

[0042] In this way, the tubular member 58A is connected to the flow path 24 of the intermediate casing 23 and extends within the annular space 59. The tubular member 58A extends to a position above the outer peripheral end surface 42 of the non-load side bearing bracket 40. Therefore, the tubular member 58A is connected to the outer peripheral end surface 42 of the non-load side bearing bracket 40. It has an upper end 58A-1 that is located at a position above the peripheral end surface 42.

[0043] In the second embodiment, the tubular member 58A may have a substantially constant flow path diameter from the lower end 58A-2 to the upper end 58A-1. However, the tubular member 58A may have a throttle portion as described with reference to Fig. 4. The throttle portion can increase the flow rate of the coolant 27 that flows in from the lower end 58A-2 of the tubular member 58A.

[0044] For example, as shown in FIG. 7, the non-load side bearing bracket 40 of the second embodiment includes a protruding extension 44 that extends laterally beyond the outer circumferential surface of the motor frame 34. The tubular member 58A is inserted into a through-hole (number omitted in FIG. 7) in the extension 44. Within this through-hole, the tubular member 58A is positioned in direct contact with the non-load side bearing bracket 40.

[0045] FIG. 8 is a cross-sectional view of the non-load side bearing bracket 40. FIG. 8 also shows a cooling jacket 57. In the second embodiment, the tubular member 58A is simply passed through the through-hole 44a of the extension portion 44 and may be fixed to the upper and lower protrusions 34a-1 and 34a-2 of the motor frame 34, for example, in the manner described with reference to FIG. 6. The tubular member 58A is positioned relative to the through-hole 44a so that it is at least partially maintained in contact with the inner surface of the through-hole 44a. For this purpose, the tubular member 58A may be fixed to the through-hole 44a via an appropriate fastener.

[0046] In this embodiment, the extensions 44 are formed as protruding portions provided at two locations on the outer periphery of the non-load side bearing bracket 40. However, in other embodiments, the extensions 44 may extend over the entire outer periphery of the non-load side bearing bracket 40.

[0047] Because the coolant 27 flows inside the tubular member 58A, which is in contact with the extension 44, the non-load side bearing bracket 40 is cooled by the coolant 27 via the tubular member 58A and the extension 44. The coolant 27 flowing out from the upper end 58A-1 of the tubular member 58A also comes into contact with the extension 44, thereby cooling the non-load side bearing bracket 40. The coolant 27 flowing out from the upper end 58A-1 of the tubular member 58A also comes into contact with the motor frame 34, thereby cooling the motor frame 34.

[0048] As described above, the tubular member 58A may have a throttling portion. In this case, the inner diameter of the through hole 44a may be set according to the outer diameter of the throttling portion. The inner diameter of the through hole 44a is set according to the outer diameter of the portion of the tubular member 58A located within the through hole 44a. Furthermore, in the second embodiment, the tubular member 58A is disposed within the through hole 44a in direct contact with the non-load side bearing bracket 40. However, as long as sufficient heat exchange between the coolant 27 and the non-load side bearing bracket 40 is achieved, an appropriate member made of a thermally conductive material may be disposed within the through hole 44a so as to be in contact with the tubular member 58A and the non-load side bearing bracket 40. Furthermore, the portion of the extension 44 that contacts the tubular member 58A does not have to have the form of a through hole 44a. For example, it may have the form of a notch that can receive the tubular member 58A.

[0049] As described above, the intermediate casing 23, together with the pump casing 22, defines the flow path of water transported by the main impeller 21. Therefore, the intermediate casing 23, particularly the side plate 23b forming the bottom of the intermediate casing 23, is constantly cooled by water, and the coolant 27 is cooled by water through the intermediate casing 23. The coolant 27, which has been heated by heat exchange, is drawn into the suction port 60a of the circulation impeller 60 by the centrifugal force of the circulation impeller 60 from the cooling jacket 57 through the suction flow path 24a between the intermediate casing 23 and the inner casing 26, and then discharged from the discharge port 60b to the discharge flow path 24b. The discharged coolant 27 is cooled in the discharge flow path 24b between the inner casing 26 and the side plate 23b, and flows into the tubular member 58A through the opening 371. The coolant 27 flows through the tubular member 58A. The coolant 27 flows out of the upper end 58A-1 of the tubular member 58A and contacts the extension 44, thereby cooling the non-load side bearing bracket 40. The coolant 27 flows out of the upper end 58A-1 of the tubular member 58A and contacts the extension 44, thereby cooling the non-load side bearing bracket 40. The coolant 27 flows out of the upper end 58A-1 of the tubular member 58A and contacts the motor frame 34, thereby cooling the motor frame 34.

[0050] Thus, according to the second embodiment, the cooling jacket 57, the circulation impeller 60, the intermediate casing 23, and the tubular member 58A form a cooling mechanism for cooling the motor section 30. This makes it possible to provide a motor pump 10A that can be operated in air. Unlike the prior art, a simple method can be used to reliably bring the coolant 27 into contact with the non-load side bearing bracket 40 and perform heat exchange. Furthermore, because the coolant 27 can cool the non-load side bearing bracket 40 while passing through the tubular member 58A, heat exchange can be performed efficiently. This improves the cooling effect of the entire motor section 30, including the non-load side bearing bracket 40.

[0051] Although the embodiments of the present invention have been described above, the above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention includes equivalents thereof. Furthermore, any combination or omission of the components described in the claims and specification is possible within the scope of solving at least part of the above-described problems or achieving at least part of the effects.

[0052] The present invention includes the following aspects. 1. A main impeller configured to be able to transport water by rotating; a pump casing that houses the main impeller; a main shaft connected to the main impeller; a counter-load side bearing that supports the rotation of the main shaft on the counter-load side; a counter-load side bearing bracket for holding a counter-load side bearing; a motor frame that houses a rotor that rotates integrally with the main shaft and a stator that is provided on the outer periphery of the rotor; a cooling jacket disposed so as to surround an outer peripheral surface of the motor frame, and defining an annular space between the motor frame and the cooling jacket and receiving a coolant; an intermediate casing disposed between the pump casing and the motor frame, the intermediate casing defining a flow path for a coolant from the at least one first opening to the at least one second opening; A motor pump comprising: a circulation impeller attached to a main shaft within the flow path; a counter-load side bearing bracket attached to the motor frame such that the counter-load side bearing bracket has a surface partially exposed within the annular space; The motor pump further comprises: at least one tubular member disposed in the annular space and having an upper end positioned above the exposed surface of the non-load side bearing bracket and a lower end; The lower end of the tubular member is arranged to open into the flow path through the second opening of the intermediate casing. Motor pump. 2. The motor pump according to 1. above, A motor pump, wherein the tubular member includes a restriction portion that increases the flow rate of the coolant from the lower end. 3. The motor pump according to 2. above, A motor pump, wherein the restriction portion forms a flow path including a tapered portion and a small diameter portion adjacent to the tapered portion, and the small diameter portion extends with a substantially constant diameter from the tip of the tapered portion to the upper end of the tubular member. 4. The motor pump according to any one of 1. to 3. above, the non-load side bearing bracket has an extension portion that extends radially outward beyond the outer circumferential surface of the motor frame; The motor pump, wherein the extension is configured to receive the tubular member in contact with the extension. 5. The motor pump according to any one of 1. to 4. above, A motor pump, wherein the intermediate casing includes an upper surface extending radially outward beyond the motor frame, and the first opening and the second opening are formed in the upper surface of the intermediate casing. 6. The motor pump according to any one of 1. to 5. above, The device includes an inner casing disposed in the intermediate casing, A motor pump, wherein the inner casing separates a flow path within the intermediate casing into a suction flow path including a first opening and a discharge flow path including a second opening. 7. The motor pump according to item 6 above, A motor pump, wherein the intermediate casing includes a side plate that forms a water flow path together with the pump casing, and the discharge flow path is formed between the side plate and the inner casing. 8. The motor pump according to any one of 1. to 7. above, The annular space contains an air layer at the top, the motor pump. [Industrial Applicability]

[0053] The present invention can be widely applied to motor pumps. [Explanation of symbols]

[0054] AL axis 10, 10A motor pump 20 Pump part 21 Main impeller 22 Pump casing 22a Intake port 22b Discharge port 23 Intermediate casing 23a Main body 23a-1 Top surface 23b Side plate 24 flow paths 24a Suction channel 24b Discharge flow path 25 Mechanical seal 26 Inner casing 26-1 position 27 Coolant 30 Motor part 31 Main shaft 32 rotor 33 Stator 34 Motor frame 34a Motor frame body 34a-1, 34a-2 convex parts 34b Top cover 37 Load side bearing bracket 38 Load side bearing 39 Mechanical seal 40 Anti-load side bearing bracket 40-1 Fixed part 41 Anti-load side bearing 42 Outer peripheral end face 43 Cable 44 Extension 44a through hole 56 Anti-load side jacket side plate 57 Cooling jacket 58, 58A Tubular member 58-1, 58A-1 top end 58-2, 58A-2 lower end 59 Annular Space 60 Circulation impeller 60a Intake port 60b outlet 70 Air Layer 321 rotor core 322 Secondary Conductor 331 Stator Core 332 stator coil 371, 372 Second opening 373, 374 First opening 580 flow path 581 Lower Channel 582 Upper Channel 582-1 Tapered section 582-2 Small diameter section 584 Bracket

Claims

1. a main impeller configured to be able to transport water by rotating; a pump casing that houses the main impeller; a main shaft connected to the main impeller; a counter-load side bearing that supports the main shaft for rotation on the counter-load side; a counter-load side bearing bracket for holding the counter-load side bearing; a motor frame that accommodates a rotor that rotates integrally with the main shaft and a stator that is provided on the outer periphery of the rotor; a cooling jacket disposed to surround an outer peripheral surface of the motor frame and defining an annular space between the motor frame and the cooling jacket for receiving a coolant; an intermediate casing disposed between the pump casing and the motor frame, the intermediate casing defining a flow path for the coolant from at least one first opening to at least one second opening; A motor pump including a circulation impeller attached to the main shaft within the flow path, the counter-load side bearing bracket is attached to the motor frame so as to have a surface partially exposed within the annular space; The motor pump further comprises: at least one tubular member disposed in the annular space and having an upper end positioned above the exposed surface of the non-load side bearing bracket and a lower end; the lower end of the tubular member is arranged to open into the flow path through the second opening of the intermediate casing. Motor pump.

2. 2. The motor pump according to claim 1, The tubular member includes a restriction that increases the flow rate of the cooling liquid from the lower end.

3. 3. The motor pump according to claim 2, a restrictor portion forming a flow passage including a tapered portion and a small diameter portion adjacent to the tapered portion, the small diameter portion extending with a substantially constant diameter from the tip of the tapered portion to the upper end of the tubular member.

4. The motor pump according to any one of claims 1 to 3, the counter-load side bearing bracket has an extension portion that extends radially outward beyond the outer circumferential surface of the motor frame, The extension is configured to receive the tubular member in contact with the extension.

5. The motor pump according to any one of claims 1 to 3, The motor pump, wherein the intermediate casing includes an upper surface extending radially outward beyond the motor frame, and the first opening and the second opening are formed in the upper surface of the intermediate casing.

6. The motor pump according to any one of claims 1 to 3, an inner casing disposed in the intermediate casing; a motor pump, wherein the inner casing separates the flow path within the intermediate casing into a suction flow path including the first opening and a discharge flow path including the second opening.

7. 7. The motor pump according to claim 6, The motor pump, wherein the intermediate casing includes a side plate that forms a water flow path together with the pump casing, and the discharge flow path is formed between the side plate and the inner casing.

8. The motor pump according to any one of claims 1 to 3, The motor pump, wherein the annular space includes an air layer at the top.

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