Submersible pump cooling fan

Abstract

To provide a cooling fan of a submerged pump which utilizes a resistance difference received by the cooling fan in air or water to deform the cooling fan into an optimal fan shape to perform forced-cooling of a motor part.SOLUTION: A submerged pump includes: a pump part 2 into which an impeller 9 is inserted; and a motor part 3 which is disposed on an upper part of the pump part 2 and houses a pump main shaft 8 and a motor 14. A cooling fan of the submerged pump includes: a hub part 26 fixed to a fan main shaft 22 which extends to an area above the motor part 3 and rotates integrally with the pump main shaft 8; and blade parts 27 which are arranged in a substantially radial form equiangularly in a circumferential direction of the hub part 26 and deform so that a diameter of the cooling fan is decreased with a predetermined force acting during rotation. The structure can efficiently cool the motor part with low power.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cooling fan for a submersible pump that efficiently cools a submersible motor both in water and in air. [Background technology]

[0002] Conventionally, submersible pumps used for drainage treatment in sewage pits, etc., have required cooling of their submersible motors during operation. Submersible motors are cooled by a natural cooling method, in which the outer periphery of the motor chamber is cooled by contacting the pumped liquid, or a forced cooling method, in which a portion of the pumped liquid is circulated in a jacket installed outside the motor chamber for cooling. However, when using the natural cooling method, the submersible motor is exposed to air when the water level in the sewage pit drops, making it impossible to cool the motor with the pumped liquid. Even when using the forced cooling method, the drop in the water level makes it impossible to efficiently draw the pumped liquid into the jacket, making it impossible to cool the submersible motor. Therefore, a cooling device for submersible motors that can continue to cool efficiently even when operating in air has been desired.

[0003] Patent document 1 discloses a submersible pump with forced cooling specifications that cools the motor by circulating cooling water or cooling oil or other cooling liquid that has been sealed in an outer casing placed outside the motor casing through the rotation of a circulation impeller.

[0004] Patent document 2 discloses a submersible pump that has an outer cover and a cooling fan attached to the outer periphery of the motor case. When the water level drops and the motor case is exposed above the water surface, the motor is operated in an open-air mode, and the cooling fan is operated to cool the motor in the open air by air blown from above the outer cover downward. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5552402 [Patent Document 2] Patent No. 4530728 Summary of the Invention [Problem to be solved by the invention]

[0006] Conventionally, submersible pumps operate while cooling the submersible motor, but when the water level drops and the submersible motor is exposed to the air, there is a risk that the submersible motor will not be sufficiently cooled and will overheat. As a result, operation had to be stopped every time the water level dropped. In this case, operation would resume when the water level rose, but the frequent start-and-stop of the motor placed a heavy load on the electrical system, leading to electrical system failure. Furthermore, when forcibly cooling while taking in part of the pumped liquid into a jacket outside the motor room, foreign matter mixed in the pumped liquid could cause blockages inside the pump, leading to reduced operating efficiency and equipment failure.

[0007] Patent Document 1 uses a forced cooling system that cools the motor by circulating a coolant pre-sealed inside the outer casing. Because this cooling system does not use pumped liquid, it is not affected by fluctuations in water level and can continue to cool the motor even during open-air operation. However, it requires the preparation of separate cooling water or cooling oil as a coolant, which increases costs. Furthermore, because cooling is performed using liquid, if pumped liquid seeps into the outer casing, the coolant inside the outer casing must be replaced. At the same time, there is a concern that the coolant inside the outer casing may leak to the outside. Furthermore, because the outer casing containing the coolant is superimposed on the outer periphery of the motor casing, the diameter and overall weight of the device increase, resulting in a large device size. Furthermore, because the circulation impeller for circulating the coolant is submerged in the communication chamber, the coolant must be drained to the outside when inspecting, replacing, or repairing the impeller, which increases the maintenance burden.

[0008] Patent Document 2 describes a technology that operates a cooling fan during air-cooled operation to cool the submersible motor while air-cooling it, allowing the motor to be cooled without using liquid. However, it requires the installation of a separate submersible motor for driving the cooling fan, which increases the complexity of the equipment and running costs due to the additional submersible motor. Furthermore, switching from submersible cooling to air-cooled cooling requires the use of a water level detector to constantly monitor the water level and control the equipment, which increases the complexity of operational control.

[0009] The present invention provides a technology for cooling submersible motors using a cooling fan that automatically changes its blade shape to optimize it for air-cooling and water-cooling the submersible motor, and provides a cooling fan for submersible pumps that can efficiently cool submersible motors using minimal power. [Means for solving the problem]

[0010] The present invention is a pump section with an impeller inserted therein, and a pump main shaft located above the pump section. and Motor and motor accommodated and a cylindrical motor casing. In a submersible pump having a motor section, a fan main shaft is provided above the motor section and rotates integrally with the pump main shaft. Axis and , The fan casing is disposed above the motor casing, with the fan shaft passing through the top and a cable box on the side; a fan cover has a plurality of vents at the top, is disposed to cover the fan casing from above, and is open below; and a cooling air passage is formed between the fan casing and the fan cover, and serves as a flow path for cooling air generated from the blades. a hub portion fixed to a fan main shaft; and blade portions arranged approximately radially at equal angles in the circumferential direction of the hub portion, the blade portions deforming so as to reduce in diameter when a predetermined force acts upon the blade portion during rotation; Consists of This allows the motor to be cooled using a cooling fan that has been optimally shaped, reducing the power required to rotate the motor. In addition, because the mechanism is simple, with the cooling fan attached above the submersible motor, it can be used with conventional submersible motors and does not require major design changes. Furthermore, the cooling air drawn in through the vent can be efficiently sent towards the motor section via the fan cover, and the fan cover can also function as a soundproof cover and a safety cover for the fan.

[0011] The wing portions are formed from a thin elastic member and fixed to the outer peripheral surface of the hub portion, so that the wing portions can change shape by themselves when subjected to the resistance force acting on them during rotation.

[0012] The engagement holes formed at the base of the wing portions are engaged with the shaft portion erected in the hub portion to allow rotation, and the wing portions are configured to rotate in a state where they protrude approximately radially due to centrifugal force.This allows the wing portions to change shape by themselves in response to the resistance force acting on them when rotating, and since the base of the wing portions can be removed from the shaft portion, maintenance and management are easy.

[0013] When submerged, the blades rotate with their diameters reduced due to the resistance of the water, thereby minimizing the resistance the blades receive and minimizing the power required for rotation. [Effects of the Invention]

[0015] The cooling fan of the submersible pump of the present invention can cool the motor while rotating in air and underwater, which have different densities, while maintaining its optimal shape. This reduces the power required for cooling. The fan shape changes automatically in response to fluctuations in the water level of the pumped liquid, allowing for efficient switching between air and water cooling. This allows for rapid response even in cases where the pump is submerged due to sudden flooding of a drainage pumping station. Furthermore, water level detection and associated control are not required, simplifying operation. Furthermore, continuous operation in both air and underwater is possible, eliminating the need for frequent starting and stopping of the motor, reducing the load on the electrical system and extending the equipment's lifespan. Furthermore, the cooling fan shares the rotational power of the pump impeller, eliminating the need for a separate motor for rotating the cooling fan, resulting in a compact and energy-efficient device. Since the pumped liquid, water, oil, etc. are not required as cooling media for the motor, there is no risk of blockages inside the pump due to foreign matter or leakage of the cooling media. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic cross-sectional view of a submersible pump according to the present invention. [Figure 2] FIG. 10 is a plan view of the cooling fan during air cooling. [Figure 3] FIG. 10 is a plan view of the cooling fan during water cooling. [Figure 4]10A and 10B are plan views of a cooling fan according to another embodiment of the present invention when air-cooling and water-cooling are performed. DETAILED DESCRIPTION OF THE INVENTION

[0017] FIG. 1 is a schematic cross-sectional view of a submersible pump according to the present invention. The submersible pump 1 according to the present invention is configured by connecting, in order from the bottom, a pump section 2, a motor section 3, and a fan section 4. The pump section 2 has a pump casing 7 consisting of a first casing 5 and a second casing 6 arranged on top of the first casing 5.

[0018] The first casing 5 houses a pump main shaft 8 that extends upward from inside the casing, and an impeller 9 that is fixed to the pump main shaft 8. A pump chamber 10 is formed inside the first casing 5, and the impeller 9 rotates to suck in a liquid such as water from an inlet port 32 below, after which the liquid is pressurized by the action of the impeller 9 and the pump chamber 10 and discharged from a discharge port 11 on the side of the impeller 9.

[0019] The second casing 6 contains an oil chamber 12 in which lubricating oil is stored and through which the pump main shaft 8 passes. A lower mechanical seal 13 is arranged around the pump main shaft 8 to prevent the liquid pumped in the pump chamber 10 from entering and the lubricating oil in the oil chamber 12 from leaking to the outside.

[0020] The motor section 3 is arranged on top of the second casing 6 and comprises a pump main shaft 8 extending upward from the pump section 2, a motor 14 that rotates an impeller 9 fixed to the pump main shaft 8, and a cylindrical motor casing 15 that houses the motor 14.

[0021] The pump main shaft 8 is rotatably supported by an upper bearing 16 provided on the upper part of the motor casing 15 and a lower bearing 17 provided on the upper part of the second casing 6 .

[0022] The motor 14 comprises a rotor 18 fixed to the pump main shaft 8 and a stator 19 fixed to the inner circumference of the motor casing 15 so as to surround the rotor 18, and is configured so as to be driven by power supplied from outside through a stator coil 20 and a cable 21 connected to a power source (not shown).

[0023] The fan section 4 comprises a fan main shaft 22 extending above the motor section 3, a cooling fan 23 fixed to the fan main shaft 22, a fan casing 24 arranged above the motor casing 15 and through whose top the fan main shaft 22 passes, and a fan cover 25 arranged to cover the fan casing 24 from above.

[0024] The fan main shaft 22 is an extension of the pump main shaft 8 above the motor unit 3, and rotates integrally with the pump main shaft 8. In this embodiment, the fan main shaft 22 is an extension of the pump main shaft 8, but a separately formed fan main shaft 22 may also be connected to the pump main shaft 8. The diameter of the fan main shaft 22 is determined appropriately according to the design conditions.

[0025] Cooling fan 23 includes hub portion 26 fixed to fan main shaft 22, and blade portions 27 protruding substantially radially from the outer periphery of hub portion 26. Hub portion 26 and blade portions 27 are formed from metal members, and blade portions 27 in particular are formed from stainless spring steel, so that cooling fan 23 is elastically deformable.

[0026] Generally, gas and liquid have different fluid densities, with liquids having a higher density. In other words, the resistance experienced by the cooling fan 23 rotating in water, which has a higher density than air, is greater than that experienced in air. Utilizing this principle, the present embodiment is configured to cool the motor unit 3 by changing the shape of the blades 27 of the elastically deformable cooling fan 23 when operating in air and when operating underwater.

[0027] The wing portions 27 are formed using corrosion-resistant stainless spring steel, for example, but are not limited to any material as long as they are elastically deformable.

[0028] The fan casing 24 is configured such that the fan main shaft 22, to which the cooling fan 23 is fixed, passes through it, and the cooling fan 23 can rotate above the fan casing 24. An upper mechanical seal 28 is disposed at the top of the fan casing 24, and is attached to the fan main shaft 22 that passes through the fan casing 24. This prevents the pumped liquid from entering the fan casing 24 when the submersible pump 1 is submerged. In this embodiment, mechanical seals (upper mechanical seal 28, lower mechanical seal 1) are used as the shaft sealing device. 3 However, to improve maintainability, a magnetic coupling system that uses the magnetic coupling force of a magnet and does not cause liquid leakage may be used, and the sealing structure is not limited.

[0029] A cable box 29 for accommodating the cable 21 is provided on the side of the fan casing 24. The cable box 29 has a seal member 3 on its outer surface. 4 The cable 21 is connected to the stator coil 20 via the cable box 29, the fan casing 24, and the motor casing 15, and is configured so that power can be supplied from a power supply source (not shown) connected to the other end.

[0030] The fan cover 25 has multiple vent holes 31 at its top and is a cover that is open at the bottom, and is attached from above to cover the cooling fan 23 and fan casing 24. The fan cover 25 is supported on the fan casing 24 by multiple support members 38 that extend from the inside of the fan cover 25, but the installation method is not limited to this. The diameter, shape, etc. of the vent holes 31 are also selected appropriately depending on the design conditions.

[0031] By disposing the fan cover 25 configured in this way above the cooling fan 23, it is possible to draw in outside air (cooling air) through the vent 31 and send it out downward when the fan is rotating. The outside air (cooling air) drawn in through the vent 31 is guided inside the fan cover 25 and then flows down along the motor casing 15. This forcibly cools the surface of the motor unit 3. In this embodiment, when the submersible pump 1 is exposed to air and is operating in air, this cooling method is used to forcibly air-cool the motor unit 3. Therefore, the motor unit 3 does not generate heat even when not submerged in water.

[0032] The inside of the fan cover 25, which serves as a flow path for the cooling air, may be a flat plate surface without any irregularities, or may have guide grooves or guide ribs that guide the air downward. Also, the fan cover 25 may be deformed by gradually decreasing (or gradually increasing) its diameter downward.

[0033] FIG. 2 is a plan view of the cooling fan according to the present invention when cooling with air. 2 shows the cooling fan 23 that cools the motor unit 3 when the submersible pump 1 is operating in open air, with the cooling fan 23 exposed to the air. The cooling fan 23 includes an annular hub unit 26 and multiple blades 27 disposed around the hub unit 26. The hub unit 26 has a center portion 35 that penetrates and is fixed to the fan main shaft 22, and rotates integrally with the fan main shaft 22. The blades 27 have bases 30 fixed to the outer periphery of the hub unit 26 by welding or the like, and are arranged at equal angles from the center portion 35 of the hub unit 26. Each blade 27 protrudes approximately radially from the outer periphery of the hub unit 26.

[0034] The blades 27 are made of stainless spring steel and formed into thin plates, so they can easily be elastically deformed, but in this embodiment, by balancing the centrifugal force acting in a direction that maintains the blade shape with the resistance force acting in a direction that changes the blade shape during air operation, elastic deformation is minimized and the required shape of the cooling fan 23 is maintained. This allows the cooling fan 23 to efficiently generate cooling air when cooling the motor unit 3.

[0035] FIG. 3 is a plan view of the cooling fan according to the present invention when water-cooled. 3 shows the cooling fan 23 submerged in water, which cools the motor 3 when the submersible pump 1 is operating underwater. In this embodiment, the blade surface 33 is configured to elastically deform due to a predetermined resistance force received in water, so that the blade portion 27 bends in the direction opposite to the rotation direction when it receives resistance.

[0036] At this time, the airflow from the center 35 of the cooling fan 23 to the tip 3 of the blade 27 9 The distance to the pump head is shorter than during air operation in Figure 2, and the diameter of the cooling fan 23 is reduced. The reduced fan diameter reduces the pumping efficiency and power consumption. However, during underwater operation when the motor unit 3 is submerged, forced cooling by the cooling fan 23 is not required. Therefore, during underwater operation, the blades 27 are intentionally curved to reduce the diameter of the cooling fan 23 and minimize the resistance force acting on the blades 27. This allows the cooling fan 23 to be driven with minimal power.

[0037] When the water level in the submersible pump 1 drops and the pump resumes air operation, the resistance experienced by the blades 27 decreases. As a result, the blades 27 elastically return to a position away from the circumferential surface of the hub 26, as shown in Figure 2. In this way, the cooling fan 23 performs forced cooling by changing its shape to the optimum fan shape for use in air and water, which have different resistances.

[0038] The cooling fan 23 in this embodiment can continue cooling by changing its fan shape both in air and underwater. Therefore, even if the water level suddenly rises during air operation and the pump switches to underwater operation, there is no need to stop operation of the submersible pump 1. Because air cooling and water cooling can be automatically switched to in response to water level fluctuations simply by changing the fan shape, cooling of the motor section 3 can be continued efficiently. Furthermore, because the cooling fan 23 shares the rotational power of the pump main shaft 8, it can continue to operate with the minimum necessary power.

[0039] The thickness and shape of the thin plates of the blades 27 may be any configuration that maintains the optimal fan shape during both air and underwater operation. The number of plates, installation intervals, etc. are selected appropriately according to design conditions.

[0040] 4 is a plan view of a cooling fan according to another embodiment when air-cooled and when water-cooled. The cooling fan 23 when air-cooled is shown by a solid line, and the cooling fan 23 when water-cooled is shown by a dashed line. When water-cooled, the cooling fan 23 rotates toward the circumferential surface of the hub portion 26 due to the resistance of the water, reducing its diameter.

[0041] In this embodiment, a substantially cylindrical engagement hole 36 is formed in the base 30 of the wing portion 27, and a shaft portion 37 is provided in the hub portion 26. The engagement hole 36 and the shaft portion 37 are formed by a well-known hinge mechanism, and by engaging the engagement hole 36 with the shaft portion 37 from above, the wing portion 27 can rotate in both the forward and reverse directions around the shaft portion 37.

[0042] The wings 27 rotatably engaged with each shaft 37 are arranged approximately radially at equal angles in the circumferential direction of the hub 26. During air cooling, the centrifugal force and resistance force generated in the wings 27 rotating in the air are balanced, allowing each of the wings 27 to rotate while maintaining a generally radially protruding state.

[0043] When the blades 27 are in a generally radially protruding state, the diameter of the fan is at its maximum, and the diameter of the fan is from the center 35 to the tip 3 9 The distance to the base 3 of the blade 27 is at its farthest position. By rotating the blade 27 in this state during air cooling, cooling air can be generated efficiently. 0 It is formed into.

[0044] On the other hand, during water cooling, the cooling fan 23 is subjected to the resistance of the water that occurs during rotation, causing it to rotate close to the circumferential surface of the hub portion 26. The diameter of the cooling fan 23 during water cooling is smaller than during air cooling, and the resistance that the fan experiences is minimized, so the cooling fan 23 can be driven with less power than during air cooling.

[0045] In this embodiment, the engaging holes 36 formed in the wing portions 27 are configured to engage with the shaft portions 37, so that when inspecting the cooling fan 23, only the desired wing portions 27 can be removed, eliminating the need for time-consuming maintenance work.

[0046] In addition, since the wing portion 27 rotates around the base portion 30 as a starting point, it may be formed of a non-elastic metal, resin, or the like. Furthermore, the rotation mechanism of the base portion 30 may use fasteners such as screws, and is not limited to this embodiment.

[0047] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. [Industrial Applicability]

[0048] The cooling fan of the present invention can be deformed to the optimal fan shape using only the driving force of the pump main shaft when the submersible pump is operating underwater or in open air, eliminating the need for additional power. In addition to being able to cool the motor with minimal power consumption, the fan uses outside air as a cooling medium, eliminating the negative impact on water quality due to leakage of cooling oil or other substances. This makes the cooling device environmentally friendly and energy-saving. Furthermore, the present invention can be easily applied to existing submersible pumps, as it can be implemented with only minor modifications to the upper mechanism of a conventional submersible pump. [Explanation of symbols]

[0049] 2 Pump section 3 Motor section 8 Pump shaft 9 Impeller 14 Motor 15 Motor casing 22 Fan shaft 24 Fan casing 25 Fan cover 26 Hub section 27 Wings 29 Cable Box 30 base 31 Ventilation hole 36 tie hole 37 Shaft

Claims

1. A submersible pump having a pump section (2) with an impeller (9) inserted therein, and a motor section (3) disposed above the pump section (2) and including a pump main shaft (8), a motor (14), and a cylindrical motor casing (15) accommodating the motor (14), a fan main shaft (22) extending above the motor section (3) and rotating integrally with the pump main shaft (8); a fan casing (24) disposed on top of the motor casing (15), through which the fan main shaft (22) passes and which has a cable box (29) on its side; a fan cover (25) having a plurality of vent holes (31) at its top, arranged to cover the fan casing (24) from above, and open below; a cooling air passage formed between the fan casing (24) and the fan cover (25) and serving as a flow path for cooling air generated from the blade portion (27); Equipped with a hub portion (26) fixed to the fan main shaft (22) at the top of the fan casing (24); Wing portions (27) are arranged approximately radially at equal angles in the circumferential direction of the hub portion (26), and deform so as to reduce in diameter when a predetermined force acts upon the hub portion (26) during rotation; Consisting of A cooling fan for a submersible pump.

2. The wing portion (27) is formed of a thin elastic member and fixed to the outer peripheral surface of the hub portion (26).

2. The cooling fan for a submersible pump according to claim 1.

3. The engaging holes (36) formed in the bases (30) of the wing parts (27) are engaged with the shaft parts (37) erected on the hub part (26) to make the wing parts rotatable, and the wing parts (27) are configured to be rotatable in a state where they project radially under the influence of centrifugal force.

2. The cooling fan for a submersible pump according to claim 1.

4. When submerged, the wing portion (27) rotates in a state where its diameter is reduced due to the resistance of the water. The cooling fan for a submersible pump according to any one of claims 1 to 3.

Images