Submersible electric pump

Abstract

To provide a submerged electric pump that allows the amount of oil to be reduced, and allows maintenance to be easily performed.SOLUTION: A submerged electric pump 100 comprises an oil storage tank 2 provided separately from a pump body 1, a first flow passage 3 extending in the axial direction of a rotating shaft 12 along a mechanical seal 14, and arranged so as to surround the mechanical seal 14, and a second flow passage 4 connecting the oil storage tank 2 and the first flow passage 3, and is constituted so as to circulate oil between the first flow passage 3 and the oil storage tank 2 via the second flow passage 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a submersible electric pump, and more particularly to a submersible electric pump equipped with a mechanical seal. [Background technology]

[0002] BACKGROUND ART Submersible electric pumps equipped with mechanical seals have been known in the past (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses an underwater pump including a motor chamber in which a motor is installed, a pump chamber, an oil chamber arranged between the motor and the pump chamber and having a mechanical seal installed inside, and an external oil chamber. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-113031 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of a configuration with an external oil chamber and an oil chamber provided within the submersible pump body, as in Patent Document 1, the structure poses the problem of the oil being sealed in more than the amount necessary to lubricate the mechanical seal. In particular, as the size of the submersible pump (submersible electric pump) increases, the oil chamber within the submersible pump body also becomes larger, resulting in a problem of an increasingly larger amount of oil being sealed in. Furthermore, because the oil is stored in the oil chamber within the submersible pump body, oil changes require the pump body to be lifted from the water and then tilted or turned on its side to drain the oil. This means that work cannot be done at the location of the submersible pump and must be performed in a factory or other location, which is labor-intensive and difficult to maintain.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a submersible electric pump that can reduce the amount of oil and can be easily maintained.

[0007] In order to achieve the above object, one aspect of the present invention provides a submersible electric pump comprising a pump body including a motor, a rotary shaft rotated by the motor, an impeller attached to the rotary shaft, and a mechanical seal surrounding the rotary shaft; an oil storage tank provided separately from the pump body; a first flow path extending in the axial direction of the rotary shaft along the mechanical seal and arranged to surround the mechanical seal; and a second flow path connecting the oil storage tank and the first flow path. and a supply passage for supplying oil to the first flow passage and a discharge passage for discharging oil from the first flow passage. a second flow path, configured to circulate oil between the first flow path and the oil storage tank via the second flow path; The pump body includes a submerged chamber disposed circumferentially around the rotary shaft between the first flow path and the motor, and the supply and discharge paths of the second flow path are disposed across the submerged chamber. .

[0008] As described above, the submersible electric pump of one aspect of the present invention includes an oil storage tank provided separately from the pump body, a first flow path extending in the axial direction of the rotary shaft along the mechanical seal and surrounding the mechanical seal, and a second flow path connecting the oil storage tank and the first flow path. Oil is circulated between the first flow path and the oil storage tank via the second flow path. This configuration eliminates the need to provide an oil chamber in the pump body, thereby reducing the amount of oil required. Furthermore, because the oil storage tank is provided separately from the pump body, the pump can be attached to submersible electric pumps of different sizes, allowing the oil storage tank to be shared. Therefore, even if the size of the submersible electric pump increases, the oil chamber in the pump body does not become larger, unlike conventional submersible electric pumps, thereby preventing an unnecessary increase in the amount of oil required. Furthermore, because the oil storage tank is separate, oil changes can be performed by simply removing the oil storage tank, which makes maintenance easier at the location where the submersible electric pump is located, unlike when tilting the pump body. This reduces the amount of oil used and simplifies maintenance. Furthermore, heat exchange between the oil and water can occur through the outer wall of the oil storage tank, which is placed underwater, allowing the oil storage tank to function as a heat exchanger by circulating the oil.

[0009] In one aspect of the present invention, the submersible electric pump preferably further includes a flow generating unit disposed in the first flow path, configured to generate a flow that circulates oil between the first flow path and the oil storage tank as the rotating shaft rotates. With this configuration, the oil can be circulated by the rotation of the rotating shaft (centrifugal force) caused by the motor, eliminating the need to provide a drive source for circulating the oil separately from the motor that rotates the rotating shaft. This simplifies the device configuration of the submersible electric pump.

[0010] In this case, the flow generating portion preferably includes a guide vane that forms a flow that causes the oil to rise, and the guide vane is configured to form a flow that circulates the oil between the oil storage tank and the first flow path in addition to the flow that causes the oil to rise. With this configuration, the oil can be circulated while being supplied to the entire mechanical seal. Furthermore, because the guide vane is configured to form a flow that causes the oil to rise and a flow that circulates the oil, the number of parts can be reduced compared to when a component that forms the flow that causes the oil to rise and a component that circulates the oil are provided separately.

[0011] In the submersible electric pump equipped with the flow generating unit, the flow generating unit is preferably attached to the rotating shaft and includes a rotating member for generating a flow that circulates the oil. With this configuration, the rotating member rotates as the rotating shaft rotates, thereby imparting velocity energy to the oil in the first flow path. This eliminates the need for a separate power source to rotate the rotating member, and enables oil to circulate with a simple configuration. Furthermore, providing the rotating member in addition to the rotating shaft and guide vanes enables smoother oil circulation.

[0012] In the submersible electric pump including the flow generating unit, preferably, The supply route is , connected to the bottom of the first flow path, supplies oil from the oil storage tank to the first flow path The discharge path is configured to , connected to the upper part of the first flow path, and discharges oil from the first flow path to the oil storage tank. It is configured as The flow generating portion is configured to raise the oil in the first flow path so that the oil flows from the supply path toward the discharge path. With this configuration, the supply path, the first flow path, and the discharge path can be formed as a continuous flow path, so that the oil can flow in one direction and circulate more smoothly.

[0013] In this case, it is preferable to have a drain portion for draining oil from the supply passage. With this configuration, when changing oil, oil remaining in the first flow passage, the second flow passage, and the piping connecting the oil storage tank to the first flow passage or the second flow passage can also be properly drained to the outside.

[0014] In one aspect of the submersible electric pump of the present invention, preferably , immersion The capacity of the water reservoir chamber is larger than the combined capacity of the first flow path and the second flow path. This configuration allows the provision of a water reservoir chamber, thereby preventing water from entering the motor. Furthermore, because the pump does not have an oil chamber, the water reservoir chamber can be made much larger than conventional pumps. This allows the time it takes for water that has entered the pump body to reach the motor to be longer than conventional pumps, thereby extending the interval between maintenance of the pump body.

[0015] In the submersible electric pump according to the above aspect, the oil volume in the oil storage tank is preferably larger than the total volume of the first flow path and the second flow path. With this configuration, the oil volume that can be stored in the oil storage tank is large, so the capacities of the first flow path and the second flow path can be minimized.

[0016] In the submersible electric pump according to the above aspect, the total capacity of the first flow path and the second flow path is preferably set to be equal to or greater than a predetermined capacity corresponding to the amount of oil expansion that occurs when the oil storage tank is filled to capacity. With this configuration, when the oil storage tank and the pump body are connected, the oil in the oil storage tank flows into the first flow path and the second flow path, creating an appropriate space within the oil storage tank. This prevents the oil volume from exceeding the full capacity of the oil storage tank if the oil expands within the oil storage tank. Furthermore, because the appropriate amount of oil is achieved by filling the oil storage tank and connecting it to the pump body, there is no need to measure the oil when refilling, making maintenance work more efficient.

[0017] In the submersible electric pump according to the above aspect, the first flow passage arranged to surround the mechanical seal preferably has an upper flow passage width smaller than a lower flow passage width. This configuration makes it possible to prevent the overall size of the first flow passage from increasing while ensuring space for installing or removing the mechanical seal from below.

[0018] In the submersible electric pump according to the above aspect, the oil storage tank preferably has a transparent portion so that the amount of liquid inside can be checked from the outside. With this configuration, the state of the oil in the oil storage tank can be easily checked from the outside when the submersible electric pump is pulled up. [Effects of the Invention]

[0019] According to the present invention, as described above, it is possible to reduce the amount of oil and also to facilitate maintenance. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram showing a submersible electric pump. [Figure 2] FIG. 2 is a diagram showing a first flow path and a second flow path. [Figure 3] FIG. 2 is a diagram showing an example of a flow generating section according to the first embodiment. [Figure 4] FIG. 10 is a cross-sectional view illustrating a flooded chamber. [Figure 5] 3A and 3B are diagrams illustrating an example of a rotating member according to the first embodiment. [Figure 6] 5A and 5B are diagrams illustrating another example of a rotating member according to the first embodiment. [Figure 7] FIG. 4 is a diagram showing another example of the submersible electric pump according to the first embodiment. [Figure 8] FIG. 10 shows a first flow path and a second flow path according to a second embodiment. [Figure 9] FIG. 10 is a diagram showing a first flow path and a second flow path according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0021] [First embodiment] A submersible electric pump 100 according to a first embodiment will be described with reference to FIGS.

[0022] As shown in Figure 1, the submersible electric pump 100 comprises a pump body 1, an oil storage tank 2, a first flow path 3, a second flow path 4, and a flow generating unit 5. The submersible electric pump 100 of the first embodiment has an external oil storage tank 2, but does not have an oil chamber inside the pump body. This reduces the amount of oil used compared to when an oil chamber is provided inside the pump body 1, and also allows oil to be supplied to the mechanical seal 14 in a pinpoint manner, resulting in more efficient oil use, reduced resource usage, and contribution to the SDGs (Sustainable Development Goals).

[0023] The pump body 1 includes a motor 11, a rotary shaft 12, an impeller 13, and a mechanical seal 14. The pump body 1 includes a motor frame 10, a seal housing 20, and a pump chamber 30.

[0024] The motor 11 is disposed within a motor frame 10 located above the pump body 1. The motor frame 10 has a cylindrical shape centered on the rotation center α of the rotating shaft 12. The motor 11 includes a stator 11a and a rotor 11b. The stator 11a has a coil and is configured to generate a magnetic field for rotating the rotor 11b when drive power is supplied. The rotor 11b is formed in a cylindrical shape, and the rotating shaft 12 is inserted through it.

[0025] The rotating shaft 12 is disposed so as to penetrate the motor frame 10, the seal housing 20, and the pump chamber 30. The seal housing 20 is formed in a substantially cylindrical shape centered on the rotation center α of the rotating shaft 12. An impeller 13 is attached to the other end of the rotating shaft 12. The rotating shaft 12 is disposed so as to extend in the vertical direction. In this specification, the direction in which the rotating shaft 12 extends is referred to as the Z direction. The side on which the motor 11 is located is referred to as the Z1 side, and the side on which the impeller 13 is attached (lower side) is referred to as the Z2 side.

[0026] The impeller 13 is provided in a pump chamber 30 located below the pump body 1. The pump chamber 30 includes an intake port 30a and an outlet port 30b. The impeller 13 imparts velocity energy to the water when it is driven to rotate. The velocity energy of the water is converted into pressure energy within the pump chamber 30, thereby applying pressure to the water and sending it out. In other words, when the impeller 13 is driven to rotate, water is sucked up through the intake port 30a of the pump chamber 30 and discharged from the outlet port 30b.

[0027] As shown in FIG. 2, the mechanical seal 14 is disposed within the seal housing 20. The mechanical seal 14 includes a stationary ring 14a, a rotating ring 14b, and a spring member 14c. The stationary ring 14a includes an upper stationary ring 140a disposed on the Z1 side and a lower stationary ring 140b disposed on the Z2 side. The upper stationary ring 140a is fixed to the seal housing 20. The lower stationary ring 140b is fixed to the seal cover 80. The stationary ring 14a is formed in an annular shape so as to surround the rotating shaft 12. The rotating ring 14b is attached to the rotating shaft 12. In other words, the rotating ring 14b is configured to rotate together with the rotating shaft 12. The rotating ring 14b is formed in an annular shape so as to surround the rotating shaft 12. The rotating ring 14b is biased toward the stationary ring 14a by the spring member 14c. The fixed ring 14a and the rotary ring 14b are provided on the Z1 side and the Z2 side, sandwiching the spring member 14c therebetween, thereby preventing liquid such as water from entering the first flow path 3 from below. Also, liquid such as water can be prevented from entering the motor 11 side.

[0028] The stationary ring 14a (upper stationary ring 140a and lower stationary ring 140b) and the rotating ring 14b are arranged to face each other in the axial direction of the rotating shaft 12. A small amount of oil is allowed to enter between the sliding surfaces of the stationary ring 14a (upper stationary ring 140a and lower stationary ring 140b) and the rotating ring 14b from the first flow path 3. This lubricates the sliding surfaces of the stationary ring 14a (upper stationary ring 140a and lower stationary ring 140b) and the rotating ring 14b, cools the sliding surfaces of the stationary ring 14a (upper stationary ring 140a and lower stationary ring 140b) and the rotating ring 14b by the oil, and seals the contact area between the mechanical seal 14 and the pump body 1.

[0029] As shown in FIG. 1, the oil storage tank 2 is a tank for storing oil to be supplied to the mechanical seal 14. The oil storage tank 2 is, for example, cylindrical. As an example, the oil storage tank 2 is provided with a lid. If a lid is provided, a connecting portion may be provided for attaching a suction pipe for sucking the oil. The oil storage tank 2 may also have a structure in which the side surface and the top surface, which do not have a lid, are integrated. The oil storage tank 2 is attached to the pump body 1 via piping. The oil storage tank 2 is provided with an inlet 2a through which oil flows in from the pump body 1 and an outlet 2b through which oil flows out of the pump body 1, and piping (for example, hoses) is connected to the inlet 2a and the outlet 2b, respectively. Note that the piping is omitted in FIG. 1, and the direction of oil flow is indicated by arrows.

[0030] The oil storage tank 2 has a transparent portion. The transparent portion of the oil storage tank 2 allows the internal fluid level, contamination, and other conditions to be checked from the outside. "Transparent" includes cases where the interior is clearly visible, and cases where the interior is not clearly visible but is so-called translucent. The entire oil storage tank does not have to be transparent. For example, the transparent portion may be made of resin, and the rest may be made of metal parts to allow for thermal cooling. The oil volume in the oil storage tank 2 is greater than the combined volume of the first flow path 3 and the second flow path 4.

[0031] Furthermore, the total capacity of the first flow path 3 and the second flow path 4 is set to be equal to or greater than a predetermined capacity corresponding to the amount of oil expansion that occurs when the oil storage tank 2 is filled to capacity. Therefore, when a full oil storage tank 2 is connected to the pump body 1, the oil in the oil storage tank 2 flows into the first flow path 3 and the second flow path 4, thereby forming an appropriate space within the oil storage tank 2. The predetermined capacity is, for example, between 10% and 30% of the total capacity of the oil storage tank 2. As an example, when the oil storage tank 2 is filled to capacity (100%) and then attached to the pump body 1, approximately 20% (20%) of the total capacity of the oil storage tank 2 may be configured to flow into the first flow path 3 and the second flow path 4. As a result, the oil volume in the oil storage tank 2 is about 80%, and an air layer is formed in the oil storage tank 2, so even if the oil expands due to temperature changes, the oil volume in the oil storage tank 2 will not exceed 100%, preventing the oil expansion from affecting the oil storage tank 2. In addition, since the oil volume is appropriate when the oil storage tank 2 is filled to capacity and connected to the pump body 1, there is no need to measure the oil when refilling, and maintenance work can be performed more efficiently.

[0032] During maintenance work, the oil storage tank 2 and pump body 1 are pulled out of the water, and the oil storage tank 2 is removed from the pump body 1 for maintenance. In this case, as one example, the oil storage tank 2 may be drained from a drain provided in the oil storage tank 2 and new oil may be sealed in, without removing the oil storage tank 2 from the pump body 1. As another example, the oil storage tank 2 may be removed from the pump body 1 and replaced as a whole. In this case, a one-touch coupler, for example, may be used to connect the oil storage tank 2 to the hose.

[0033] As shown in FIG. 2, the first flow path 3 is disposed within the seal housing 20. The first flow path 3 extends in the axial direction (Z direction) of the rotating shaft 12 along the mechanical seal 14. The flow path width W1 of the first flow path 3 is formed to be large enough to allow a finger or an installation jig to be inserted when attaching or removing the mechanical seal 14 to or from the rotating shaft 12 from below (Z2 side). The flow path width W1 of the first flow path 3 in the radial direction of the rotating shaft 12 is formed to be, for example, approximately 20 mm. Furthermore, the flow path width W1 of the first flow path 3 is formed to be smaller than the diameter R1 of the rotating shaft 12.

[0034] The second flow path 4 is disposed within the seal housing 20. The second flow path 4 is configured to connect the oil storage tank 2 (see FIG. 1) and the first flow path 3. The second flow path 4 includes a supply path 4a and a discharge path 4b. The supply path 4a is connected to a lower portion of the first flow path 3 and is configured to supply oil from the oil storage tank 2 to the first flow path 3. The supply path 4a is connected to the outlet 2b (see FIG. 1) of the oil storage tank 2 via a pipe. For convenience, in FIG. 2, the supply path 4a and the discharge path 4b are depicted as extending in opposite directions across the center of rotation α, but the directions are not limited thereto.

[0035] The discharge passage 4b ​​is connected to an upper portion of the first flow passage 3 and is configured to discharge oil from the first flow passage 3 to the oil storage tank 2. The discharge passage 4b ​​is connected to the inlet 2a (see FIG. 1) of the oil storage tank 2 via a pipe. The supply passage 4a and the discharge passage 4b ​​are configured to extend in a direction intersecting the axial direction of the rotating shaft 12. The second flow passage 4 is configured to circulate oil between the first flow passage 3 and the oil storage tank 2. The flow passage width W2 of the second flow passage 4 may be formed smaller than the flow passage width W1 of the first flow passage 3 because there is no need to consider the working space when installing or removing the mechanical seal 14.

[0036] 7, the supply passage 4a may have a branch section 4d attached to a passage communicating with the outlet 2b of the oil storage tank 2. The branch section 4d allows the oil to flow to be switched between the first passage 3 and the drain section 4c. The drain section 4c is provided with a valve, and opening the valve allows the oil to be discharged to the outside.

[0037] 2, the flow generating unit 5 is configured to generate a flow that circulates oil between the first flow path 3 and the oil storage tank 2 in accordance with the rotation of the rotary shaft 12. Note that the flow generating unit 5 is simply illustrated in FIG.

[0038] As shown in Fig. 3, the flow generating section 5 is configured by, for example, an Oil Lifter (registered trademark). The flow generating section 5 has guide vanes 51 that form an upward flow of oil, and is arranged to extend in the axial direction and surround the mechanical seal 14 (see Fig. 2). The flow generating section 5 is provided inside the first flow path 3 (see Fig. 2).

[0039] The guide vanes 51 are attached, for example, along the outer peripheral surface of the first flow path 3, obliquely to the inner peripheral wall of the seal housing 20 from bottom to top so as to surround the rotating shaft 12. Oil flows into the seal housing 20 from below. As the rotating shaft 12 rotates, centrifugal force is generated in the oil, and the oil rises along the guide vanes 51. The oil supplied from the supply path 4a rises inside the first flow path 3 along the guide vanes 51, lubricates the mechanical seal 14 (see FIG. 2), and is then discharged from the discharge path 4b.

[0040] 5 and 6, the flow generating unit 5 may include a rotating member 52 for generating a flow that circulates the oil. The rotating member 52 may be provided together with the guide vane 51 (see FIG. 3), or may be provided instead of the guide vane 51. The rotating member 52 is disposed so as to protrude radially outward from the rotary shaft 12. The rotating member 52 may be a circulation impeller 52a as shown in FIG. 5, or a ring 52b as shown in FIG. 6. The rotating member 52 may also be a protrusion that protrudes radially outward from the rotary shaft 12. When both the guide vane 51 and the rotating member 52 are provided, the flow path width W1 (see FIG. 2) of the first flow path 3 is set to, for example, approximately the sum of the widths of the guide vane 51 and the rotary member 52.

[0041] The rotating member 52 is attached to the rotating shaft 12. The rotating member 52 may be attached directly to the rotating shaft 12 or via a separate member. That is, the rotating member 52 may be attached so as to rotate with the rotation of the rotating shaft 12. If a circulation impeller 52a is provided, it is attached between the spring member 14c and the rotating ring 14b of the mechanical seal 14 and is also attached directly to the rotating shaft 12. If a ring 52b is provided, it is attached along the outer peripheral surface of the rotating ring 14b of the mechanical seal 14. As an example, the rotating member 52 is fixed to the rotating ring 14b by the pressing force of the spring member 14c and rotates together with the rotating ring 14b around the rotation center α. The rotating member 52 generates centrifugal force by rotating together with the rotating shaft 12, causing the oil to rise along the mechanical seal 14.

[0042] 1 and 2, oil is supplied from the oil storage tank 2 to the pump body 1 via the supply passage 4a of the second flow passage 4. The oil then flows into the first flow passage 3, rises due to the guide vane 51 (see FIG. 3) and flows into the discharge passage 4b. The oil then flows from the discharge passage 4b ​​into the oil storage tank 2, where it circulates.

[0043] As shown in Figures 1 and 4, a flooding chamber 40 is provided in the space between the seal housing 20 and the motor frame 10. The flooding chamber 40 can collect liquid such as water if it enters the seal housing 20 and then leaks out toward the motor 11. The capacity of the flooding chamber 40 is larger than the combined capacity of the first flow path 3 and the second flow path 4. By increasing the capacity of the flooding chamber 40, the time it takes for liquid such as water to reach the motor 11 can be extended.

[0044] 4, the supply path 4a and the discharge path 4b (second flow path 4) are provided so as to cross the flooding reservoir chamber 40. The flooding reservoir chamber 40 has a through-hole 40a in the center into which the rotating shaft 12 is inserted, and collects liquid such as water that has entered between the through-hole 40a and the rotating shaft 12.

[0045] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0046] As described above, in the first embodiment, the submersible electric pump 100 includes the oil storage tank 2 provided separately from the pump body 1, the first flow path 3 extending in the axial direction of the rotating shaft 12 along the mechanical seal 14 and surrounding the mechanical seal 14, and the second flow path 4 connecting the oil storage tank 2 and the first flow path 3. The oil required to lubricate the mechanical seal 14 is supplied from the oil storage tank 2, eliminating the need to provide an oil chamber in the pump body 1 and reducing the amount of oil required. Furthermore, because the oil storage tank 2 is provided separately from the pump body 1, the submersible electric pump 100 can be attached to submersible electric pumps 100 of different sizes, allowing the oil storage tank 2 to be shared. Therefore, even if the size of the submersible electric pump 100 increases, the oil chamber in the pump body 1 does not become larger, unlike in conventional submersible electric pumps 100, preventing an increase in the amount of oil more than necessary. Furthermore, because the oil storage tank 2 is a separate body, oil changes can be performed by simply removing the oil storage tank 2, which means that maintenance can be easily performed at the location where the submersible electric pump 100 is located, unlike when tilting the pump body 1. This allows the amount of oil to be reduced and maintenance to be performed easily. Furthermore, because heat exchange can occur between the oil and water via the outer wall of the oil storage tank 2, which is placed underwater, the oil storage tank 2 can function as a heat exchanger by circulating the oil.

[0047] As described above, the first embodiment further includes a flow generating unit 5 disposed in the first flow path 3, which is configured to generate a flow that circulates oil between the first flow path 3 and the oil storage tank 2 as the rotating shaft 12 rotates. This allows the oil to be circulated by the rotation (centrifugal force) of the rotating shaft 12 caused by the motor 11, eliminating the need to provide a drive source for circulating the oil separately from the motor 11 that rotates the rotating shaft 12. This allows the device configuration of the submersible electric pump 100 to be simplified.

[0048] In the first embodiment, as described above, the flow generating section 5 includes the guide vane 51 that forms a flow that causes oil to rise, and the guide vane 51 is configured to form a flow that circulates the oil between the oil storage tank 2 and the first flow path 3 in addition to the flow that causes the oil to rise. This allows the oil to be circulated while being supplied to the entire mechanical seal 14. Furthermore, because the guide vane 51 is configured to form a flow that causes the oil to rise and a flow that circulates the oil, the number of parts can be reduced compared to when a member that forms a flow that causes the oil to rise and a member that circulates the oil are provided separately.

[0049] In the first embodiment, as described above, the flow generating unit 5 is attached to the rotating shaft 12 and includes the rotating member 52 for generating a flow that circulates the oil. As a result, the rotating member 52 also rotates as the rotating shaft 12 rotates, so that velocity energy can be imparted to the oil in the first flow path 3. This eliminates the need to provide a separate power source for rotating the rotating member 52, and allows the oil to circulate with a simple configuration. Furthermore, by providing the rotating member 52 in addition to the rotating shaft 12 and the guide vane 51, the oil can be circulated more smoothly.

[0050] In the first embodiment, as described above, the second flow path 4 includes a supply path 4a connected to a lower portion of the first flow path 3 and supplying oil from the oil storage tank 2 to the first flow path 3, and a discharge path 4b connected to an upper portion of the first flow path 3 and discharging oil from the first flow path 3 to the oil storage tank 2, and the flow generating unit 5 is configured to raise the oil in the first flow path 3 so that the oil flows from the supply path 4a toward the discharge path 4b. This allows the supply path 4a, the first flow path 3, and the discharge path 4b to be formed as a continuous flow path, which makes it possible to make the oil flow in one direction and circulate the oil more smoothly.

[0051] In the first embodiment, as described above, the supply passage 4a has the drain portion 4c that drains oil from the supply passage 4a. This allows oil remaining in the first passage 3, the second passage 4, and the piping connecting the oil storage tank 2 to the first passage 3 or the second passage 4 to be properly discharged to the outside during oil change.

[0052] In the first embodiment, as described above, the pump body 1 further includes a flood chamber 40 that is circumferentially disposed between the first flow path 3 and the motor 11 to surround the rotary shaft 12, and the capacity of the flood chamber 40 is larger than the combined capacity of the first flow path 3 and the second flow path 4. Thus, providing the flood chamber 40 can prevent water from entering the motor 11. Furthermore, because the pump body 1 is configured without an oil chamber, the flood chamber 40 can be made much larger than conventional pumps. This allows the time it takes for water that has entered the pump body 1 to reach the motor 11 to be longer than conventional pumps. As a result, the intervals between maintenance of the pump body 1 can be extended.

[0053] In the first embodiment, as described above, the volume of oil in the oil storage tank 2 is larger than the total volume of the first flow path 3 and the second flow path 4. As a result, the volume of oil that can be stored in the oil storage tank 2 is large, and the volumes of the first flow path 3 and the second flow path 4 can be minimized.

[0054] In the first embodiment, as described above, the total capacity of the first flow path 3 and the second flow path 4 is set to be equal to or greater than a predetermined capacity corresponding to the amount of oil expansion that occurs when the oil storage tank 2 is filled to capacity. As a result, when the oil storage tank 2 and the pump body 1 are connected, the oil in the oil storage tank 2 flows into the first flow path 3 and the second flow path 4, thereby forming an appropriate space within the oil storage tank 2. This makes it possible to prevent the oil volume from exceeding the full capacity of the oil storage tank 2 if the oil expands within the oil storage tank 2. Furthermore, because the appropriate amount of oil is obtained when the oil storage tank 2 is filled to capacity and connected to the pump body 1, there is no need to measure the amount of oil when refilling, making maintenance work more efficient.

[0055] In the first embodiment, as described above, the oil storage tank 2 has a transparent portion so that the amount of liquid inside can be checked from the outside. This makes it possible to easily check the state of the oil inside the oil storage tank 2 from the outside when the submersible electric pump 100 is pulled up.

[0056] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to Fig. 8. Unlike the first embodiment, the second embodiment has a first flow path 3 in which an upper flow path width W4 is smaller than a lower flow path width W3.

[0057] As shown in FIG. 8, in the second embodiment, the first flow path 3 is formed so that the upper flow path width W4 is smaller than the lower flow path width W3. The lower flow path width W3 is large enough to allow a finger or a jig to be inserted when attaching or removing the mechanical seal 14 to or from the rotating shaft 12 from below (the Z2 side). The upper flow path width W4 is not particularly limited and may be formed smaller than the size that allows a finger or a jig to be inserted. Note that the flow generating section 5 and the mechanical seal 14 are omitted in FIG. 8. The flow generating section 5 of the second embodiment is the same as any of the flow generating sections 5 of the first embodiment. The mechanical seal 14 has the same structure as that of the first embodiment.

[0058] The other configurations of the second embodiment are the same as those of the first embodiment.

[0059] (Effects of the second embodiment) In addition to the same effects as in the first embodiment, the second embodiment can also achieve the following effects: That is, in the second embodiment, as described above, the first flow path 3, which is arranged to surround the mechanical seal 14, has an upper flow path width W4 that is smaller than a lower flow path width W3, so that it is possible to prevent the overall size of the first flow path from increasing while ensuring space when attaching or detaching the mechanical seal 14 from below.

[0060] (Variation) The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than the above description of the embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0061] For example, in the first and second embodiments, the width of the second flow passage is constant, but the present invention is not limited to this. For example, the width of the second flow passage may change midway. In this case, as shown in FIG. 9, the width of the discharge passage on the oil storage tank side may be smaller than the width of the discharge passage on the first flow passage side.

[0062] In the first or second embodiment, the flow path width of the second flow path is smaller than the flow path width of the first flow path, but the present invention is not limited to this. In the present invention, the flow path width of the second flow path may be the same as the flow path width of the first flow path, or the flow path width of the second flow path may be larger than the flow path width of the first flow path.

[0063] In addition, in the first and second embodiments, an example is shown in which the oil storage tank and the pump body are lifted up for maintenance, but the present invention is not limited to this. In the present invention, maintenance may be performed by lifting up only the oil storage tank. [Explanation of symbols]

[0064] 1 Pump body 2 Oil storage tanks 3 First flow path 4 Second flow path 4a Supply route 4b Exhaust channel 4c Drain section 5 Flow generation section 11 Motor 12 Rotation axis 13 Impeller 14 Mechanical seal 40 Flooded Room 51 Guide vane 52 Rotating member 100 Submersible electric pump

Claims

1. a pump body including a motor, a rotary shaft rotated by the motor, an impeller attached to the rotary shaft, and a mechanical seal surrounding the rotary shaft; an oil storage tank provided separately from the pump body; a first flow path extending in the axial direction of the rotary shaft along the mechanical seal and disposed so as to surround the mechanical seal; a second flow path that connects the oil storage tank and the first flow path and includes a supply path that supplies oil to the first flow path and a discharge path that discharges oil from the first flow path; The oil is circulated between the first flow path and the oil storage tank via the second flow path, the pump body includes a submerged chamber disposed circumferentially so as to surround the rotary shaft between the first flow path and the motor, The supply passage and the discharge passage of the second flow path are arranged to cross the submersible reservoir chamber.

2. 2. The submersible electric pump according to claim 1, further comprising a flow generating unit disposed in the first flow path, configured to generate a flow that circulates the oil between the first flow path and the oil storage tank as the rotating shaft rotates.

3. the flow generating portion includes a guide vane that forms an upward flow of the oil, 3. The submersible electric pump according to claim 2, wherein the guide vanes are configured to form a flow that circulates the oil between the oil storage tank and the first flow path in addition to a flow that raises the oil.

4. The submersible electric pump according to claim 2 , wherein the flow generating unit is attached to the rotary shaft and includes a rotary member for generating a flow that circulates the oil.

5. The supply path is connected to a lower portion of the first flow path and is configured to supply the oil from the oil storage tank to the first flow path; the discharge passage is connected to an upper portion of the first flow passage and is configured to discharge the oil from the first flow passage to the oil storage tank; The submersible electric pump according to any one of claims 2 to 4, wherein the flow generating unit is configured to raise the oil in the first flow path so that the oil flows from the supply path toward the discharge path.

6. The submersible electric pump according to claim 5 , wherein the supply passage has a drain portion for draining the oil.

7. An underwater electric pump described in any one of claims 1 to 4, wherein the capacity of the flooded reservoir chamber is greater than the total capacity of the first flow path and the second flow path.

8. The submersible electric pump according to any one of claims 1 to 4, wherein a volume of the oil in the oil storage tank is greater than a total volume of the first flow path and the second flow path.

9. The submersible electric pump according to any one of claims 1 to 4, wherein a total capacity of the first flow path and the second flow path is set to be equal to or greater than a predetermined capacity corresponding to an amount of oil expansion when the oil storage tank is filled to capacity.

10. The submersible electric pump according to any one of claims 1 to 4, wherein the first flow path has a flow path width at an upper portion that is smaller than a flow path width at a lower portion.

11. The submersible electric pump according to any one of claims 1 to 4, wherein the oil storage tank has a transparent portion so that the amount of liquid inside can be confirmed from the outside.

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