Power supply for submersible pumps

Abstract

The present invention relates to a power supply device and a power supply method for supplying power to a submerged pump used to transport a liquefied gas such as liquefied ammonia, liquefied natural gas (LNG), or liquid hydrogen. A power supply device (15) comprises: a first electrical contact (21) which is secured to a submerged pump (7) and which is electrically connected to a motor (7a) of the submerged pump (7); a second electrical contact (22) contacting the first electrical contact (21); and a power cable (25) electrically connected to the second electrical contact (22). At least a portion of the second electrical contact (22) is disposed inside a pump column (10) housing the submerged pump (7).

Description

[[Technical Field]]

[0001] The present invention relates to a power supply device and a power supply method for supplying electric power to a submersible pump for transferring liquefied gas such as liquefied ammonia, liquefied natural gas (LNG) and liquid hydrogen. [[Background Art]]

[0002] Natural gas is widely used as a fuel for thermal power generation and as a chemical raw material. Further, ammonia and hydrogen are expected to serve as energy sources that do not generate carbon dioxide, which causes global warming. Applications of hydrogen as an energy source include fuel cells and turbine power generation. Since natural gas, ammonia, and hydrogen are in a gaseous state at normal temperature, they are cooled and liquefied for storage and transportation. Liquefied gas such as liquefied natural gas (LNG), liquefied ammonia, and liquid hydrogen is once stored in a liquefied gas storage tank, and then transferred to a power plant, a factory, or the like by a pump.

[0003] FIG. 37 is a schematic diagram showing a conventional example of a liquefied gas storage tank storing liquefied gas and a pump for pumping the liquefied gas. A pump 500 is installed in a vertical pump column 505 provided in a liquefied gas storage tank 501. A power cable 515 is connected to an electric motor of the pump 500, and electric power is supplied from the power cable 515 to the electric motor of the pump 500. The power cable 515 extends from the inside of the pump column 505 to the outside, and is connected to a power source (not shown) (e.g., a commercial power source).

[0004] The inside of the pump column 505 is filled with liquefied gas, and the entire pump 500 and the power cable 515 are immersed in the liquefied gas. Therefore, the pump 500 is a submersible pump that can be operated in liquefied gas. When the pump 500 is operated, the liquefied gas in the liquefied gas storage tank 501 is sucked into the pump column 505, rises inside the pump column 505, and is discharged from the pump column 505.

[0005] The pump 500 is housed within the pump column 505 with a cable 508 connected to its upper part. The upper part of the cable 508 is wound around a cable holder 511 that extends from the top cover 510 into the pump column 505 and is held in place by the cable holder 511. The lower end of the cable 508 is connected to the pump 500. Therefore, the cable 508, like the pump 500, is housed within the pump column 505.

[0006] Cable 508 is used when moving the pump 500 into the pump column 505 and when pulling it up from the pump column 505. By keeping cable 508 connected to the pump 500, the work of connecting cable 508 to the pump 500 is eliminated when pulling up the pump 500. While the pump 500 is in operation, cable 508 is immersed in liquefied gas inside the pump column 505 together with the pump 500.

[0007] Figure 38 illustrates the process of moving the pump 500 into the pump column 505 and the process of lifting the pump 500 out of the pump column 505. When installing the pump 500 inside the pump column 505, and when lifting the pump 500 out of the pump column 505 for maintenance or other purposes, the upper end of the cable 508 is connected to the hoisting machine 512. The pump 500 is suspended by the cable 508 and is raised and lowered inside the pump column 505 by the hoisting machine 512. As the pump 500 rises and falls, the power cable 515 also rises and falls.

[0008] Pump 500 is a machine containing consumable parts and therefore requires regular maintenance. When pump 500 is first installed in pump column 505, and when pump 500 is returned to pump column 505 after maintenance, it is necessary to prevent air from entering pump column 505 along with pump 500. If air enters pump column 505 along with pump 500, the moisture in the air will be cooled and solidified by the ultra-low temperature liquefied gas, hindering the rotational operation of pump 500. In particular, if the liquefied gas is liquid hydrogen, nitrogen and oxygen in the air may liquefy or solidify and mix with the liquefied gas. Solidification of nitrogen and oxygen can damage equipment, and furthermore, if liquefied oxygen mixes with liquid hydrogen, there is a risk of explosion.

[0009] Even when removing the pump 500 from the pump column 505 for maintenance or other purposes, it is necessary to prevent ambient air from entering the pump column 505. That is, the pump 500, which has been in contact with the liquefied gas, is at an extremely low temperature, and if air comes into contact with such a pump 500, components such as nitrogen in the air may liquefy on the surface of the pump 500 and drip into the pump column 505, mixing with the liquefied gas. In particular, if the liquefied gas is liquid hydrogen, the following problems may occur. That is, since the temperature of liquid hydrogen is below -253°C, the pump 500 that has just been removed from the pump column 505 will also be at an extremely low temperature, equivalent to that of liquid hydrogen. If air comes into contact with such an extremely low-temperature pump 500, not only nitrogen in the air but also oxygen will liquefy. If liquefied oxygen drips into the liquefied gas storage tank 501 and mixes with the liquid hydrogen, there is a possibility of explosion, which is extremely dangerous.

[0010] Therefore, in order to avoid the above-mentioned problems, before the pump 500 is brought into the pump column 505, a dry-up is performed in which the pump 500 is exposed to purge gas in a purge container to remove any air and moisture in contact with the pump 500. Similarly, immediately after the pump 500 is removed from the pump column 505, a hot-up is performed in which the pump 500 is exposed to purge gas in a purge container to heat the pump 500. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Patent No. 3197645 [Patent Document 2] Patent No. 3198248 [Patent Document 3] Patent No. 3472379 [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] The above-mentioned dry-up and hot-up methods can resolve the problems associated with the pump 500. However, similar problems can occur not only with the pump 500 but also with the power cable 515. Drying and hot-up the power cable 515 within the purge container is one solution. However, pump columns 505 for liquefied gases are generally very long vertically, sometimes reaching tens of meters. As a result, the power cable 515 connected to the pump 500, which is installed at the bottom of the pump column 505, is also inevitably long. The process of housing such a long power cable 515 within the purge container is very laborious. Furthermore, the power cable 515 may be damaged during the loading and unloading of the pump 500 into the pump column 505. Damage to the power cable 515 necessitates repair or replacement of the power cable 515, which involves labor and cost.

[0013] Therefore, the present invention provides a power supply system that eliminates the need to bring the power cable into the pump column together with the pump, and also eliminates the need to remove the power cable from the pump column together with the pump. Place provide. [Means for solving the problem]

[0014] In one embodiment, a power supply device is provided for supplying power to a submersible pump used for transferring liquefied gas, comprising: a first electrical contact fixed to the submersible pump and electrically connected to the electric motor of the submersible pump; a second electrical contact fixed to a pump column housing the submersible pump and in contact with the first electrical contact; and a power cable electrically connected to the second electrical contact.

[0015] In one embodiment, the first electrical contact and the second electrical contact are in contact with each other and are movable relative to each other in the longitudinal direction of the pump column. In one embodiment, the second electrical contact is located within the pump column, and at least a portion of the power cable is located within the pump column. In one embodiment, a portion of the second electrical contact is located outside the pump column, and the entire power cable is located outside the pump column. In one embodiment, the power supply device further includes a positioning mechanism that determines the relative positions of the first electrical contact and the second electrical contact in the circumferential direction of the submersible pump. In one embodiment, the power cable is fixed to the inner or outer surface of the pump column. In one embodiment, the power cable has structural resistance to temperatures below the boiling point of the liquefied gas.

[0016] In one embodiment, the power supply device further comprises a spring that presses the first electrical contact against the second electrical contact, and a support structure that movably supports the first electrical contact, with a horizontal gap between the first electrical contact and the support structure. In one embodiment, the first electrical contact has a tapered surface, and the second electrical contact has an inverse tapered surface that conforms to the shape of the tapered surface. In one embodiment, the power supply device further includes a positioning mechanism that determines the relative positions of the first electrical contact and the second electrical contact in the circumferential direction of the submersible pump, the positioning mechanism having a combination of a guide rail and a guide follower, and the horizontal gap between the first electrical contact and the support structure is larger than the horizontal gap between the guide rail and the guide follower.

[0017] In one embodiment, the power supply device further comprises a spring that presses the second electrical contact against the first electrical contact, and a support structure that movably supports the second electrical contact, with a horizontal gap between the second electrical contact and the support structure. In one embodiment, the second electrical contact has a tapered surface, and the first electrical contact has an inverse tapered surface that conforms to the tapered surface. In one embodiment, the power supply device further comprises a positioning mechanism that determines the relative positions of the first electrical contact and the second electrical contact in the circumferential direction of the submersible pump, the positioning mechanism having a combination of a guide rail and a guide follower, and the horizontal gap between the second electrical contact and the support structure is larger than the horizontal gap between the guide rail and the guide follower.

[0018] In one embodiment, the power supply device further comprises a plurality of pulleys and a power supply connector arranged within the pump column, and a power supply line electrically connected to the power supply connector, wherein the power cable is an endless power cable, the endless power cable is movably supported by the plurality of pulleys, and the second electrical contact has a plurality of electrical connectors connected to the endless power cable, one of the plurality of electrical connectors being detachably connected to the first electrical contact, and another of the plurality of electrical connectors being detachably connected to the power supply connector. In one embodiment, the power cable comprises a metal wiring embedded in the inner surface of the pump column and a power supply line electrically connected to the metal wiring.

[0019] In one aspect, the power supply device further comprises a suspension structure extending vertically along the inner surface of the pump column, the suspension structure is detachably arranged in the pump column, and the second electrical contact is held by the suspension structure. In one aspect, the suspension structure extends from the upper part to the lower part of the pump column. In one aspect, the suspension structure has a guide groove or a guide rail with which a guide follower provided on the submerged pump engages.

[0020] In one aspect, the second electrical contact is an electrode rail extending vertically from the upper part to the lower part of the pump column. In one aspect, the first electrical contact is configured to be movable on the electrode rail while engaging with the electrode rail. In one aspect, the second electrical contact is an electrode bar embedded in the inner surface of the pump column.

[0021] In one aspect, a pump system is provided, comprising a submerged pump for transferring liquefied gas, a pump column having the submerged pump accommodated therein, and the above power supply device. In one aspect, a liquefied gas tank facility is provided, comprising a liquefied gas storage tank for storing liquefied gas, a pump column arranged in the liquefied gas storage tank, a submerged pump arranged in the pump column for transferring the liquefied gas, and the above power supply device.

[0022] In one aspect, there is provided a power supply method for supplying power to a submerged pump used for transferring liquefied gas, wherein the lifting device lowers the submerged pump in the pump column, and brings the first electrical contact fixed to the submerged pump and electrically connected to the motor of the submerged pump into contact with the second electrical contact fixed to the pump column, and supplies power to the motor from the power cable electrically connected to the second electrical contact via the second electrical contact and the first electrical contact.

[0023] In one embodiment, when the submersible pump is lowered to the operating position within the pump column, the first electrical contact comes into contact with the second electrical contact. In one embodiment, when the submersible pump is raised from the operating position by the lifting device, the first electrical contact is disconnected from the second electrical contact. In one embodiment, the liquefied gas has electrical insulating properties. [Effects of the Invention]

[0024] According to the present invention, an electrical connection between the first electrical contact and the second electrical contact is established when the first electrical contact and the second electrical contact come into contact. Since the first electrical contact can be disconnected from the second electrical contact, the power cable and the second electrical contact can be permanently installed on the pump column. Therefore, when loading the pump into the pump column and when loading the pump out of the pump column, it is not necessary to load and unload the power cable together with the pump. [Brief explanation of the drawing]

[0025] [Figure 1] This is a schematic diagram showing one embodiment of a liquefied gas tank facility. [Figure 2] This figure shows one embodiment of a pump system including a pump column, a submersible pump, and a power supply device. [Figure 3A] Figure 3A shows the first and second electrical contacts as viewed from the radial direction of the pump column. [Figure 3B] Figure 3B shows the first and second electrical contacts as viewed from the radial direction of the pump column. [Figure 4] This diagram illustrates how the submersible pump shown in Figure 2 is housed within the pump column. [Figure 5] This figure shows another embodiment of the power supply device. [Figure 6] This diagram illustrates how the submersible pump shown in Figure 5 is housed within the pump column. [Figure 7]This is a cross-sectional view showing one embodiment in which three pairs of first and second electrical contacts are provided. [Figure 8] This is an enlarged view showing one embodiment of the first contact assembly and the second contact assembly. [Figure 9] This figure shows one embodiment of a pump system including a first contact assembly and a second contact assembly. [Figure 10] This is an enlarged view showing how the first electrical contact of the first contact assembly makes contact with the second electrical contact of the second contact assembly. [Figure 11] This is a cross-sectional view along line AA in Figure 9. [Figure 12] This is an enlarged view showing other embodiments of the first contact assembly and the second contact assembly. [Figure 13] This is an enlarged view showing how the first electrical contact of the first contact assembly makes contact with the second electrical contact of the second contact assembly. [Figure 14] This figure shows one embodiment of a pump system, including other embodiments of the power supply device. [Figure 15] This diagram illustrates the process of removing a submersible pump from the pump column. [Figure 16] This diagram illustrates the process of removing a submersible pump from the pump column. [Figure 17] This diagram illustrates the process of removing a submersible pump from the pump column. [Figure 18] Figure 18 shows a pump system with yet another embodiment of the power supply device. [Figure 19] Figure 18 is an enlarged cross-sectional view of the side wall of the pump column. [Figure 20] Figure 18 is a horizontal cross-sectional view of the pump column. [Figure 21] This figure shows a pump system with yet another embodiment of the power supply device. [Figure 22] Figure 21 is a front view showing one embodiment of the suspension structure. [Figure 23] Figure 21 is a cross-sectional view along line BB. [Figure 24]Figure 21 is a cross-sectional view along the CC line. [Figure 25] This diagram shows how the suspension structure, along with the second electrical contact, is removed from the pump column. [Figure 26] This diagram shows how the first electrical contact, which is fixed to the submersible pump, is brought into contact with the second electrical contact on the suspension structure. [Figure 27] This is a horizontal cross-sectional view showing the guide follower engaged with the guide groove. [Figure 28] This figure shows one embodiment of a pump system, including yet another embodiment of the power supply device. [Figure 29] Figure 28 is a horizontal cross-sectional view of the pump system. [Figure 30] This figure shows one embodiment of a pump system, including yet another embodiment of the power supply device. [Figure 31] Figure 30 is a horizontal cross-sectional view of the pump system shown. [Figure 32] This figure shows one embodiment of a pump system, including yet another embodiment of the power supply device. [Figure 33] Figure 32 is a horizontal cross-sectional view of the pump system shown. [Figure 34] This figure shows one embodiment of a pump system, including yet another embodiment of the power supply device. [Figure 35] Figure 33 is a horizontal cross-sectional view of the pump system shown. [Figure 36] This diagram shows how the first electrical contact, which is fixed to the submersible pump, is brought into contact with the second electrical contact on the suspension structure. [Figure 37] This is a schematic diagram showing a conventional example of a liquefied gas storage tank where liquefied gas is stored and a pump for drawing up the liquefied gas. [Figure 38] Figure 37 illustrates the process of moving the pump into the pump column and the process of removing the pump from the pump column. [Modes for carrying out the invention]

[0026] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a schematic diagram showing one embodiment of a liquefied gas tank facility. The liquefied gas tank facility 1 comprises a liquefied gas storage tank 3 for storing liquefied gas and a pump system 5 for pumping the liquefied gas from the liquefied gas storage tank 3. Examples of liquefied gases include liquefied ammonia, liquid hydrogen, liquid nitrogen, liquefied natural gas, liquefied ethylene gas, and liquefied petroleum gas. The pump system 5 comprises a submersible pump 7 for transferring liquefied gas, a pump column 10 in which the submersible pump 7 is housed, and a power supply device 15 for supplying power to the submersible pump 7.

[0027] The pump column 10 is installed inside the liquefied gas storage tank 3 where the liquefied gas is stored. The pump column 10 is a hollow container extending vertically, with its upper part protruding upward from the liquefied gas storage tank 3. The submersible pump 7 is installed at the bottom of the pump column 10. Note that the pump column 10 may have a shape other than that shown in Figure 1.

[0028] Figure 2 shows one embodiment of a pump system 5 including a pump column 10, a submersible pump 7, and a power supply device 15. The upper part of the pump column 10 is provided with a purge gas introduction port 12 and a liquefied gas discharge port 13. The upper end opening of the pump column 10 is closed by a top cover 14. A suction valve 6 is provided at the bottom of the pump column 10. The configuration of the suction valve 6 is not particularly limited, but in this embodiment, the suction valve 6 is of a type that opens due to the weight of the submersible pump 7. In one embodiment, the suction valve 6 may be an actuator-driven valve (e.g., an electric valve). In one embodiment, the purge gas introduction port 12 may not be provided.

[0029] The upper end of the submersible pump 7 is connected to a suspension cable 17 suspended from the top cover 14. Power is supplied to the motor 7a of the submersible pump 7 from a power source (not shown) via a power supply device 15. When power is supplied via the power supply device 15, the submersible pump 7 is driven and pumps up the liquefied gas that flows into the pump column 10 from the suction valve 6. The liquefied gas pumped up by the submersible pump 7 is discharged from the pump column 10 through the liquefied gas discharge port 13. The type of motor 7a of the submersible pump 7 is not particularly limited, and an AC motor (e.g., induction motor or synchronous motor) or a DC motor (e.g., brushless DC motor) can be used.

[0030] The power supply device 15 includes a first electrical contact 21 electrically connected to the motor 7a of the submersible pump 7, a second electrical contact 22 that contacts the first electrical contact 21, and a power cable 25 electrically connected to the second electrical contact 22. The first electrical contact 21 is fixed to the submersible pump 7, and the second electrical contact 22 is fixed to the pump column 10. The first electrical contact 21 is fixed to the outer surface of the submersible pump 7 and protrudes radially outward from the outer surface of the submersible pump 7. The second electrical contact 22 is located inside the pump column 10 and fixed to the inner surface of the pump column 10. The second electrical contact 22 is located radially outward from the submersible pump 7. The first electrical contact 21 is movable integrally with the submersible pump 7, while the position of the second electrical contact 22 is fixed.

[0031] The first electrical contact 21 and the second electrical contact 22 are in contact with the liquefied gas, but the liquefied gas used in this embodiment has electrical insulating properties. Therefore, no leakage current occurs through the first electrical contact 21 and the second electrical contact 22.

[0032] A portion of the power cable 25 is located inside the pump column 10, while the other portion is located outside the pump column 10. The power cable 25 extends through the side wall of the pump column 10, and a portion of the power cable 25 is fixed to the inner surface of the pump column 10. The end of the power cable 25 is located inside the pump column 10 and is connected to the second electrical contact 22. The power cable 25 has structural resistance to temperatures below the boiling point of the liquefied gas. More specifically, the power cable 25 is configured to maintain its flexible properties even at extremely low temperatures. Specific examples of the power cable 25 include power cables with flexible twisted conductors, power cables with a multi-layered polyester resin tape winding structure, and power cables with a stainless steel braided structure that is resistant to trauma.

[0033] The power supply device 15 further includes a positioning mechanism 30 that determines the relative positions of the first electrical contact 21 and the second electrical contact 22 in the circumferential direction of the submersible pump 7. This positioning mechanism 30 has a guide rail 30A fixed to the inner surface of the pump column 10 and a guide follower 30B that engages with the guide rail 30A. The guide rail 30A extends in the longitudinal direction (i.e., vertical direction) of the pump column 10. The guide follower 30B protrudes radially outward from the outer surface of the submersible pump 7. The guide follower 30B may be detachable from the submersible pump 7 or it may be an integral part of the submersible pump 7. The guide follower 30B has a shape that allows it to move along the guide rail 30A in the longitudinal direction of the pump column 10 while engaging with the guide rail 30A. To achieve higher positioning accuracy, multiple positioning mechanisms 30, each comprising multiple sets of guide rails 30A and guide followers 30B, may be provided.

[0034] Figure 3A shows the first electrical contact 21 and the second electrical contact 22 as viewed from the radial direction of the pump column 10. The first electrical contact 21 has a first contact surface 21a that extends along the longitudinal direction of the pump column 10. Similarly, the second electrical contact 22 has a second contact surface 22a that extends along the longitudinal direction of the pump column 10. In this embodiment, the first electrical contact 21 has a flat plate shape, and the second electrical contact 22 has a clamp shape that sandwiches the first electrical contact 21. In one embodiment, the second electrical contact 22 may have a flat plate shape, and the first electrical contact 21 may have a clamp shape that sandwiches the second electrical contact 22.

[0035] As shown in Figure 3B, the first electrical contact 21 can be moved toward the second electrical contact 22 until the first contact surface 21a contacts the second contact surface 22a. The first contact surface 21a and the second contact surface 22a are parallel to each other and extend in the longitudinal direction of the pump column 10. Therefore, the first electrical contact 21 and the second electrical contact 22 are movable relative to each other in the longitudinal direction of the pump column 10 while in contact with each other.

[0036] Figure 4 illustrates how the submersible pump 7 shown in Figure 2 is housed within the pump column 10. As shown in Figure 4, with the guide follower 30B engaged with the guide rail 30A, the submersible pump 7 is lowered within the pump column 10 by a lifting device 31 connected to the suspension cable 17. The lifting device 31 is equipped with a hoist or winch, etc. To prevent ambient air from entering the pump column 10, a purge gas (for example, an inert gas such as nitrogen gas or helium gas) is supplied into the pump column 10 through the purge gas introduction port 12.

[0037] The first electrical contact 21 descends together with the submersible pump 7. The circumferential position of the submersible pump 7 within the pump column 10 is fixed by the guide rail 30A and guide follower 30B that constitute the positioning mechanism 30. Therefore, the first electrical contact 21 can contact the second electrical contact 22 when the submersible pump 7 is lowered within the pump column 10. When the submersible pump 7 is lowered to its operating position within the pump column 10 (the position of the submersible pump 7 shown in Figure 2), the first electrical contact 21 contacts the second electrical contact 22. This establishes an electrical connection between the first electrical contact 21 and the second electrical contact 22 (see Figure 2). Power is supplied from the power cable 25 to the motor 7a of the submersible pump 7 via the second electrical contact 22 and the first electrical contact 21, thereby operating the submersible pump 7.

[0038] When the submersible pump 7 is removed from the pump column 10 for repair or maintenance, the submersible pump 7 is lifted up from inside the pump column 10 by a lifting device 31 connected to the suspension cable 17, as in Figure 4. When the submersible pump 7 is lifted from the operating position by the lifting device 31, the first electrical contact 21 is disconnected from the second electrical contact 22.

[0039] Thus, according to this embodiment, when the first electrical contact 21 and the second electrical contact 22 make contact, an electrical connection between the first electrical contact 21 and the second electrical contact 22 is established. Since the first electrical contact 21 can be disconnected from the second electrical contact 22, the power cable 25 and the second electrical contact 22 can be permanently installed on the pump column 10. Therefore, when the pump 7 is brought into the pump column 10 and when the pump 7 is removed from the pump column 10, it is not necessary to bring the power cable 25 into and out of the pump column 10 together with the pump 7.

[0040] Figure 5 shows another embodiment of the power supply device 15. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment described with reference to Figures 1 to 4, so a redundant description is omitted. As shown in Figure 5, in this embodiment, a portion of the second electrical contact 22 is located outside the pump column 10, and the entire power cable 25 is located outside the pump column 10. The power cable 25 is fixed to the outer surface of the pump column 10. The second electrical contact 22 extends through the side wall of the pump column 10. Therefore, the second electrical contact 22 has an outer portion located outside the pump column 10 and an inner portion located inside the pump column 10. The end of the power cable 25 is connected to the outer portion of the second electrical contact 22. The inner portion of the second electrical contact 22 has the second contact surface 22a described with reference to Figures 3A and 3B.

[0041] Figure 6 illustrates how the submersible pump 7 shown in Figure 5 is housed within the pump column 10. As shown in Figure 6, with the guide follower 30B engaged with the guide rail 30A, the submersible pump 7 is lowered within the pump column 10 by a lifting device 31 connected to the suspension cable 17. To prevent ambient air from entering the pump column 10, a purge gas (for example, an inert gas such as nitrogen or helium) is supplied into the pump column 10 through the purge gas introduction port 12.

[0042] The first electrical contact 21 descends together with the submersible pump 7. The circumferential position of the submersible pump 7 within the pump column 10 is fixed by the guide rail 30A and guide follower 30B that constitute the positioning mechanism 30. Therefore, the first electrical contact 21 can contact the second electrical contact 22. When the submersible pump 7 is lowered to its operating position within the pump column 10 (the position of the submersible pump 7 shown in Figure 5), the first electrical contact 21 contacts the second electrical contact 22. This establishes an electrical connection between the first electrical contact 21 and the second electrical contact 22 (see Figure 5). Power is supplied from the power cable 25 to the motor 7a of the submersible pump 7 via the second electrical contact 22 and the first electrical contact 21, thereby operating the submersible pump 7.

[0043] When removing the submersible pump 7 from the pump column 10 for repair or maintenance, the submersible pump 7 is lifted up from inside the pump column 10 by a lifting device 31 connected to a suspension cable 17, as in Figure 6. When the submersible pump 7 is lifted from the operating position by the lifting device 31, the first electrical contact 21 is disconnected from the second electrical contact 22.

[0044] Figures 1 to 6 show one pair of first electrical contacts 21 and second electrical contacts 22. However, if the motor 7a of the submersible pump 7 is configured to be driven by three-phase AC power, then, as shown in Figure 7, three pairs of first electrical contacts 21 and second electrical contacts 22 are provided. Multiple positioning mechanisms 30, each having a guide rail 30A and a guide follower 30B, may also be provided. Four or more positioning mechanisms 30 may be provided to improve the accuracy of determining the relative positions of the first electrical contacts 21 and second electrical contacts 22 in the circumferential direction of the submersible pump 7.

[0045] Next, further embodiments of the power supply device 15 will be described with reference to Figures 8 to 11. The configuration and operation of these embodiments, which are not specifically described, are the same as those of the embodiments described with reference to Figures 1 to 7, so their redundant descriptions will be omitted.

[0046] The power supply device 15 comprises a first contact assembly 41 fixed to the submersible pump 7 and a second contact assembly 42 fixed to the pump column 10. The first contact assembly 41 comprises a first electrical contact 21, a spring 44 that presses the first electrical contact 21 against the second electrical contact 22, and a support structure 45 that movably supports the first electrical contact 21. The support structure 45 is fixed to the submersible pump 7. More specifically, the support structure 45 has a base bracket 47 fixed to the submersible pump 7 and an insulator 48 held by the base bracket 47. The insulator 48 has a through hole 48a through which the first electrical contact 21 extends. The first electrical contact 21 has a flange 50 at its upper end, which prevents the first electrical contact 21 from falling from the insulator 48.

[0047] The first electrical contact 21 has a vertically extending shape, and its tip (lower end) is composed of a tapered surface 54. The tapered surface 54 has the shape of a frustocone. The tapered surface 54 may have other shapes, such as a frustopyrocone. The first electrical contact 21 is electrically connected to a lead wire 57 connected to the electric motor 7a. There is a horizontal gap G1 between the first electrical contact 21 and the support structure 45. In this embodiment, since the first electrical contact 21 is inserted into a through hole 48a of the insulator 48, the horizontal gap G1 is formed between the inner surface forming the through hole 48a and the outer surface of the first electrical contact 21.

[0048] The second contact assembly 42 has a second electrical contact 22 and an electrical contact holder 59 that holds the second electrical contact 22. The second electrical contact 22 has an inverse tapered surface 55 that conforms to the tapered surface 54 of the first electrical contact 21. The electrical contact holder 59 is fixed to the pump column 10 and extends from the pump column 10 toward the submersible pump 7. The second electrical contact 22 is electrically connected to a power cable 25 via a conductor 60 located inside the electrical contact holder 59. The power cable 25 is located outside the pump column 10.

[0049] In this embodiment, to improve the electrical connection between the first electrical contact 21 and the second electrical contact 22, the first electrical contact 21 may have a multi-contact 63 mounted on its tapered surface 54. The multi-contact 63 is made of an elastic conductive structure and can ensure a reliable electrical connection between the first electrical contact 21 and the second electrical contact 22. Such multi-contacts 63 are available on the market. Both ends of the spring 44 are in contact with the first electrical contact 21 and the support structure 45, biasing the first electrical contact 21 toward the second electrical contact 22. Furthermore, the presence of the spring 44 eliminates the need to precisely position the base bracket 47 fixed to the submersible pump 7 and the electrical contact holder 59 fixed to the pump column 10 in the vertical direction.

[0050] Figure 8 shows one pair of first contact assemblies 41 and second contact assemblies 42. However, if the motor 7a of the submersible pump 7 is configured to be driven by three-phase AC power, three pairs of first contact assemblies 41 and second contact assemblies 42 are provided. Similarly, three power cables 25 are provided, connected to the three second contact assemblies 42.

[0051] As shown in Figure 9, when the submersible pump 7 is lowered to a predetermined operating position within the pump column 10, the first electrical contact 21 makes electrical contact with the second electrical contact 22. More specifically, as shown in Figure 10, the tapered surface 54 of the first electrical contact 21 makes electrical contact with the reverse tapered surface 55 of the second electrical contact 22. In this embodiment, the tapered surface 54 of the first electrical contact 21 makes electrical contact with the reverse tapered surface 55 of the second electrical contact 22 through a multi-contact 63. In one embodiment, the multi-contact 63 may not be provided.

[0052] The tapered surface 54 of the first electrical contact 21 is pressed against the reverse tapered surface 55 of the second electrical contact 22 by the spring 44, thereby ensuring contact between the first electrical contact 21 and the second electrical contact 22. Furthermore, even when the submersible pump 7 shakes in the vertical direction, the spring 44 can maintain contact between the first electrical contact 21 and the second electrical contact 22.

[0053] As shown in Figure 10, when the first electrical contact 21 and the second electrical contact 22 are in electrical contact, there is a horizontal gap G1 between the first electrical contact 21 and the support structure 45. This gap G1 allows the support structure 45 to move relative to the first electrical contact 21. The reason for providing this gap G1 is as follows: When the submersible pump 7 is started or when an earthquake occurs, the submersible pump 7 shakes, and an excessive load is placed on the first electrical contact 21 and the second electrical contact 22, which are in contact with each other. As a result, the first electrical contact 21 and / or the second electrical contact 22 may be damaged. The gap G1 between the first electrical contact 21 and the support structure 45 allows the submersible pump 7 to move relative to the pump column 10. Therefore, the excessive load on the first electrical contact 21 and the second electrical contact 22 caused by the shaking of the submersible pump 7 is reduced.

[0054] Figure 11 is a cross-sectional view taken along line AA in Figure 9. In this embodiment, the gap G1 (see Figure 10) between the first electrical contact 21 and the support structure 45 is larger than the horizontal gap between the guide rail 30A and the guide follower 30B that constitute each positioning mechanism 30. Therefore, the load caused by the vibration of the submersible pump 7 is absorbed by the guide rail 30A and the guide follower 30B and not applied to the first electrical contact 21 and the second electrical contact 22. As a result, excessive load on the first electrical contact 21 and the second electrical contact 22 caused by the vibration of the submersible pump 7 is substantially prevented.

[0055] Next, yet another embodiment of the power supply device 15 will be described with reference to Figures 12 and 13. The configuration and operation of this embodiment, which will not be specifically described, are the same as those of the embodiment described with reference to Figures 8 to 11, so their redundant explanation will be omitted. As shown in Figure 12, the power supply device 15 includes a first contact assembly 41 fixed to the submersible pump 7 and a second contact assembly 42 fixed to the pump column 10.

[0056] The second contact assembly 42 comprises a second electrical contact 22, a spring 74 that presses the second electrical contact 22 against the first electrical contact 21, and a support structure 75 that movably supports the second electrical contact 22. The support structure 75 is fixed to the pump column 10. More specifically, the support structure 75 has a base bracket 77 fixed to the pump column 10 and an insulator 78 held by the base bracket 77. The insulator 78 has a through hole 78a through which the second electrical contact 22 extends.

[0057] The second electrical contact 22 has a vertically extending shape, and its tip (upper end) is composed of a tapered surface 84. The tapered surface 84 has the shape of a frustocone. The tapered surface 84 may have other shapes, such as a frustopyrocone. The second electrical contact 22 is electrically connected to the power cable 25. There is a horizontal gap G1 between the second electrical contact 22 and the support structure 75. In this embodiment, since the second electrical contact 22 is inserted into a through hole 78a of the insulator 78, the horizontal gap G1 is formed between the inner surface forming the through hole 78a and the outer surface of the second electrical contact 22.

[0058] The first contact assembly 41 has a first electrical contact 21 and an electrical contact holder 89 that holds the first electrical contact 21. The first electrical contact 21 has an inverse tapered surface 85 that conforms to the tapered surface 84 of the second electrical contact 22. The electrical contact holder 89 is fixed to the submersible pump 7 and extends from the submersible pump 7 toward the pump column 10. The first electrical contact 21 is electrically connected to a lead wire 57 connected to the electric motor 7a.

[0059] In this embodiment, in order to improve the electrical connection between the second electrical contact 22 and the first electrical contact 21, the second electrical contact 22 may have a multi-contact 93 mounted on its tapered surface 84. The multi-contact 93 is made of an elastic conductive structure and can ensure a reliable electrical connection between the second electrical contact 22 and the first electrical contact 21. Both ends of the spring 74 are in contact with the second electrical contact 22 and the support structure 75, biasing the second electrical contact 22 toward the first electrical contact 21. Furthermore, the presence of the spring 74 eliminates the need to precisely position the electrical contact holder 89 fixed to the submersible pump 7 and the base bracket 77 fixed to the pump column 10 in the vertical direction.

[0060] As shown in Figure 13, when the submersible pump 7 is lowered to a predetermined operating position within the pump column 10, the first electrical contact 21 makes electrical contact with the second electrical contact 22. More specifically, the reverse tapered surface 85 of the first electrical contact 21 makes electrical contact with the tapered surface 84 of the second electrical contact 22. In this embodiment, the reverse tapered surface 85 of the first electrical contact 21 makes electrical contact with the tapered surface 84 of the second electrical contact 22 through a multi-contact 93. In one embodiment, the multi-contact 93 may not be provided.

[0061] The tapered surface 84 of the second electrical contact 22 is pressed against the reverse tapered surface 85 of the first electrical contact 21 by the spring 74, thereby ensuring contact between the first electrical contact 21 and the second electrical contact 22. Furthermore, even when the submersible pump 7 shakes in the vertical direction, the spring 74 can maintain contact between the first electrical contact 21 and the second electrical contact 22.

[0062] As shown in Figure 13, when the first electrical contact 21 and the second electrical contact 22 are in electrical contact, there is a horizontal gap G1 between the second electrical contact 22 and the support structure 75. This gap G1 allows the first electrical contact 21 and the second electrical contact 22 to move relative to the support structure 75, that is, the submersible pump 7 to move relative to the pump column 10. Therefore, excessive load on the first electrical contact 21 and the second electrical contact 22 due to the vibration of the submersible pump 7 can be reduced.

[0063] In this embodiment, the gap G1 between the second electrical contact 22 and the support structure 75 is larger than the horizontal gap between the guide rail 30A and the guide follower 30B that constitute each positioning mechanism 30 shown in Figure 11. Therefore, the load caused by the vibration of the submersible pump 7 is absorbed by the guide rail 30A and the guide follower 30B and not applied to the first electrical contact 21 and the second electrical contact 22. As a result, excessive load on the first electrical contact 21 and the second electrical contact 22 caused by the vibration of the submersible pump 7 is substantially prevented.

[0064] Further embodiments of the power supply device 15 will be described with reference to Figures 14 to 17. The configuration and operation of these embodiments, which are not specifically described, are the same as those of the embodiments described with reference to Figures 1 to 7, so redundant descriptions will be omitted.

[0065] The power supply device 15 further comprises a plurality of pulleys 96 and power supply connectors 97 arranged within the pump column 10, and a power supply line 99 electrically connected to the power supply connectors 97. The power supply line 99 extends from the outside to the inside of the pump column 10. The power supply line 99 extends through the cover 14. In one embodiment, the power supply line 99 may extend through the side wall of the pump column 10.

[0066] The power cable 25 is an endless power cable (hereinafter referred to as the endless power cable 25). The endless power cable 25 is movably supported by a plurality of pulleys 96. The second electrical contact 22 has a plurality of electrical connectors 100A, 100B connected to the endless power cable 25. In this embodiment, two electrical connectors 100A, 100B are connected to the endless power cable 25. These electrical connectors 100A, 100B are movable together with the endless power cable 25. Three or more electrical connectors may be connected to the endless power cable 25.

[0067] The entire endless power cable 25 and the multiple electrical connectors 100A and 100B are located within the pump column 10. One of the multiple electrical connectors 100A and 100B, electrical connector 100A, is detachably connected to a first electrical contact 21. The first electrical contact 21 is an electrical connector that can be electrically connected to each of the multiple electrical connectors 100A and 100B. Another of the multiple electrical connectors 100A and 100B, electrical connector 100B, is detachably connected to a power supply connector 97.

[0068] Power is supplied to the motor 7a of the submersible pump 7 via the power supply line 99, power supply connector 97, electrical connector 100B, power cable 25, electrical connector 100A, and the first electrical contact 21.

[0069] When removing the submersible pump 7 from the pump column 10, as shown in Figure 15, the top cover 14 is removed and the worker disconnects the upper electrical connector 100B and the power supply connector 97. Next, as shown in Figure 16, the submersible pump 7 is lifted up inside the pump column 10 using the lifting device (see reference numeral 31 in Figure 4), and the lower electrical connector 100A and the first electrical contact 21 are positioned near the upper opening of the pump column 10. As the submersible pump 7, electrical connector 100A, and the first electrical contact 21 rise, the electrical connector 100B moves downward. As shown in Figure 17, the worker disconnects the lower electrical connector 100A and the first electrical contact 21. Then, the submersible pump 7 is removed from the pump column 10 using the lifting device.

[0070] When the submersible pump 7 is brought into the pump column 10, the above steps are performed in the reverse order. That is, the submersible pump 7 is lowered using the lifting device (see reference numeral 31 in Figure 4) to position the submersible pump 7 and the first electrical contact 21 near the upper opening of the pump column 10. The worker connects the electrical connector 100A to the first electrical contact 21. Next, the submersible pump 7 is lowered within the pump column 10 using the lifting device to position the submersible pump 7 in the predetermined operating position, and the electrical connector 100B is raised to near the upper opening of the pump column 10. The worker connects the electrical connector 100B to the power supply connector 97. This electrically connects the submersible pump 7, the power cable 25, and the power supply line 99.

[0071] Further embodiments of the power supply device 15 will be described with reference to Figures 18 to 20. The configuration and operation of these embodiments, which are not specifically described, are the same as those of the embodiments described with reference to Figures 1 to 7, so their redundant descriptions will be omitted. Figure 18 is a diagram showing a pump system with yet another embodiment of the power supply device 15, Figure 19 is an enlarged cross-sectional view of the side wall of the pump column 10 shown in Figure 18, and Figure 20 is a horizontal cross-sectional view of the pump column 10 shown in Figure 18.

[0072] As shown in Figure 18, the portion of the power cable 25 located inside the pump column 10 is embedded in the inner surface of the pump column 10. More specifically, as shown in Figures 19 and 20, each power cable 25 has a metal wire 25A embedded in the inner surface of the pump column 10 and a power supply line 25B electrically connected to the metal wire 25A. The metal wire 25A is embedded in a wiring groove (not shown) formed on the inner surface of the pump column 10. The metal wire 25A and the wiring groove extend longitudinally along the pump column 10, and the lower end of the metal wire 25A is connected to the second electrical contact 22. The upper end of the metal wire 25A is connected to the power supply line 25B. The power supply line 25B extends from the inside to the outside of the pump column 10 and is electrically connected to a power source (not shown).

[0073] According to this embodiment, since the metal wiring 25A extending inside the pump column 10 is embedded inside the pump column 10, damage to the power cable 25 caused by sliding contact between the power cable 25 and the pump column 10 or the submersible pump 7 can be prevented.

[0074] Further embodiments of the power supply device 15 will be described with reference to Figures 21 to 27. The configuration and operation of these embodiments, which are not specifically described, are the same as those of the embodiments described with reference to Figures 1 to 7, so their redundant descriptions will be omitted. Figure 21 shows a pump system with yet another embodiment of the power supply device 15. In Figure 21, the submersible pump 7 is drawn with a dotted line for the purpose of illustrating the power supply device 15.

[0075] As shown in Figure 21, the power supply device 15 includes a suspension structure 105 that is removablely arranged inside the pump column 10. This suspension structure 105 extends longitudinally along the inner surface of the pump column 10, from the top to the bottom of the pump column 10. The suspension structure 105 is suspended from the top of the pump column 10. In one embodiment, the suspension structure 105 may be suspended from the top cover 14. The second electrical contact 22 is held in the suspension structure 105. The suspension structure 105 has a plurality of guide grooves 107 into which a guide follower (described later) provided on the submersible pump 7 engages.

[0076] Figure 22 is a front view showing one embodiment of the suspension structure 105 shown in Figure 21, Figure 23 is a cross-sectional view along line BB of Figure 21, and Figure 24 is a cross-sectional view along line CC of Figure 21. The suspension structure 105 has a longitudinally extended structure 111 that extends longitudinally along the pump column 10, and an electrical contact holder 112 that protrudes inward from the bottom of the longitudinally extended structure 111 in the radial direction of the pump column 10. The second electrical contact 22 is held in the electrical contact holder 112.

[0077] The longitudinally extended structure 111 and the electrical contact holder 112 in this embodiment have an arc-shaped horizontal cross-sectional shape, but in one embodiment, the longitudinally extended structure 111 and the electrical contact holder 112 may have other horizontal cross-sectional shapes. The longitudinally extended structure 111 may be divided into a plurality of segments along the longitudinal direction. These segments are detachably connected by fasteners such as a combination of bolts and nuts.

[0078] The power cable 25 extends through the gap between the rear side of the suspension structure 105 and the inner surface of the pump column 10. Furthermore, as shown in Figure 21, the power cable 25 extends upward through the top cover 14. In one embodiment, as described with reference to Figures 18 to 20, a portion of the power cable 25 may consist of metal wiring embedded on the rear side of the suspension structure 105.

[0079] The longitudinally extended structure 111 has a through hole 111a at its lower part. The power cable 25 extends from the back side of the suspension structure 105 through the through hole 111a to the front side of the suspension structure 105 and is connected to the second electrical contact 22. The longitudinally extended structure 111 has a plurality of guide grooves 107 that engage with a guide follower (described later) provided on the submersible pump 7. These guide grooves 107 extend parallel to the longitudinal direction and are formed on the inner surface of the longitudinally extended structure 111. The second electrical contact 22 may have the same configuration as the second electrical contact 22 described with reference to Figures 8 to 11.

[0080] As shown in Figure 25, after removing the submersible pump 7 from the pump column 10, the suspension structure 105, along with the second electrical contact 22, can be removed from the pump column 10. Therefore, maintenance such as cleaning, repairing, or replacing the second electrical contact 22 can be performed.

[0081] After maintenance of the second electrical contact 22, the suspension structure 105 is placed inside the pump column 10, and then, as shown in Figure 26, the submersible pump 7 is lowered inside the pump column 10, bringing the first electrical contact 21, which is fixed to the submersible pump 7, into contact with the second electrical contact 22 on the suspension structure 105. This establishes an electrical connection between the motor 7a of the submersible pump 7 and the power cable 25. The first electrical contact 21 may have the same configuration as the first electrical contact 21 described with reference to Figures 8 to 11.

[0082] As shown in Figure 26, the submersible pump 7 has a plurality of guide followers 114 that engage with the guide grooves 107 (see Figures 21 and 24) formed on the inner surface of the suspension structure 105. Although only one guide follower 114 is shown in Figure 26, a plurality of guide followers 114 are provided corresponding to the plurality of guide grooves 107. These guide followers 114 protrude from the side of the submersible pump 7.

[0083] As shown in Figure 27, the guide follower 114 engages with the guide groove 107, thereby achieving the relative positioning of the submersible pump 7 with respect to the suspension structure 105 and the second electrical contact 22. In one embodiment, instead of the guide groove 107, a guide rail may be provided on the inner surface of the suspension structure 105 (more specifically, the inner surface of the longitudinal extension structure 111). A specific example of the guide rail configuration is the guide rail 30A shown in Figure 11. The guide follower 114 engages with the guide rail, thereby achieving the relative positioning of the submersible pump 7 with respect to the suspension structure 105 and the second electrical contact 22.

[0084] Further embodiments of the power supply device 15 will be described with reference to Figures 28 and 29. The configuration and operation of these embodiments, which are not specifically described, are the same as those of the embodiments described with reference to Figures 1 to 7, so their redundant descriptions will be omitted. Figure 28 is a diagram showing one embodiment of the pump system, including further embodiments of the power supply device 15, and Figure 29 is a horizontal cross-sectional view of the pump system shown in Figure 28.

[0085] In Figure 28, the submersible pump 7 moves up and down along electrode rails 120, which are fixedly positioned inside the pump column 10 and serve as second electrical contacts. The upper part of the electrode rails 120 is supported by a beam 121 that crosses the pump column 10, and each electrode rail 120 extends longitudinally from the top to the bottom of the pump column 10. The electrode rails 120 are made of a conductive material and are connected to a power cable 25. The electrode rails 120 are electrically connected to an external power source (not shown) outside the pump column 10 via the power cable 25.

[0086] The first electrical contact 21 of the submersible pump 7, which contacts the electrode rail 120, is a conductor. When the submersible pump 7 is installed at the bottom of the pump column 10, the first electrical contact 21 and the electrode rail 120, which is the second electrical contact, are electrically connected. The portion of the electrode rail 120 other than the lower part may be covered with an insulating material. The first electrical contact 21 is configured to be movable on the electrode rail 120 while engaged with the electrode rail 120, which is the second electrical contact.

[0087] As shown in Figure 29, the engagement of the first electrical contact 21 with the electrode rail 120, which is the second electrical contact, prevents the submersible pump 7 from rotating or swaying during raising and lowering, allowing the submersible pump 7 to be accurately positioned at a predetermined operating location and ensuring reliable power supply. Furthermore, it is no longer necessary to raise or lower the submersible pump 7 while the power cable is connected to it, eliminating the need for a power cable winder. The first electrical contact 21 connected to the submersible pump 7 is pressed against the electrode rail 120 by a spring or the like (not shown), and if the first electrical contact 21 wears out, it can be replaced. In other words, there is no need for a worker to descend to the bottom of the pump column 10 for maintenance of the first electrical contact 21.

[0088] Figure 30 is a diagram showing one embodiment of the pump system, including yet another embodiment of the power supply device 15, and Figure 31 is a horizontal cross-sectional view of the pump system shown in Figure 30. The configuration of this embodiment, which is not specifically described, is the same as that of the embodiment described with reference to Figures 28 and 29, so redundant descriptions are omitted.

[0089] In this embodiment, the inner diameter of the pump column 10 is slightly larger than the outer diameter of the submersible pump 7. Therefore, all electrode rails 120 can be fixed to the inner surface of the pump column 10 without using the beam 121 described earlier for the arrangement of the electrode rails 120. In this case, the power cable 25 for connecting the electrode rails 120 to an external power source of the pump column 10 can be passed through the side wall of the pump column 10 at any height.

[0090] Figure 32 is a diagram showing one embodiment of the pump system, including yet another embodiment of the power supply device 15, and Figure 33 is a horizontal cross-sectional view of the pump system shown in Figure 32. The configuration of this embodiment, which is not specifically described, is the same as that of the embodiment described with reference to Figures 30 and 31, so redundant descriptions are omitted.

[0091] The power supply device 15 of this embodiment includes a positioning mechanism 30 that restrains the circumferential movement of the submersible pump 7, a first electrical contact 21 fixed to the submersible pump 7, and an electrode bar 123 as a second electrical contact embedded in the inner surface of the pump column 10. As shown in Figure 33, the positioning mechanism 30 has a guide rail 30A fixed to the pump column 10 and a guide follower 30B fixed to the submersible pump 7. The detailed configuration of the positioning mechanism 30 is the same as that of the previously described embodiment, so a redundant explanation will be omitted.

[0092] The electrode bar 123, which serves as the second electrical contact, is made of metal embedded in the inner surface of the pump column 10 and extends vertically along the longitudinal direction of the pump column 10. The electrode bar 123 has an exposed surface located on the inner surface of the pump column 10. There is no step between the exposed surface of the electrode bar 123 and the inner surface of the pump column 10, and the exposed surface of the electrode bar 123 and the inner surface of the pump column 10 form a smooth curved surface. This configuration prevents air from stagnating or accumulating around the electrode bar 123, and prevents the reaction of air and liquefied gases such as liquid hydrogen in the vicinity of the electrode bar 123.

[0093] The electrode bar 123 may extend from the top to the bottom of the pump column 10, similar to the guide rail 30A, or it may be positioned at the same height as the submersible pump 7 when installed at the bottom of the pump column 10. A power cable 25 for connecting the electrode bar 123 to an external power source for the pump column 10 extends through the side wall of the pump column 10.

[0094] Figure 34 is a diagram showing one embodiment of the pump system, including yet another embodiment of the power supply device 15, and Figure 35 is a horizontal cross-sectional view of the pump system shown in Figure 34. The configuration of this embodiment, which is not specifically described, is the same as that of the embodiment described with reference to Figures 32 and 33, so redundant descriptions are omitted.

[0095] The power supply device 15 of this embodiment includes a positioning mechanism 30 that restrains the circumferential movement of the submersible pump 7, a first electrical contact 21 fixed to the submersible pump 7, and a second electrical contact 22 fixed to the inner surface of the pump column 10. The positioning mechanism 30 has a guide rail 30A fixed to the pump column 10 and a guide follower 30B fixed to the submersible pump 7. The detailed configuration of the positioning mechanism 30 is the same as that of the previously described embodiment, so a redundant explanation will be omitted.

[0096] The first electrical contact 21 is fixed to the side of the submersible pump 7 and faces diagonally downward. The second electrical contact 22 is fixed to the inclined upper surface of a base 130 that protrudes radially inward from the inner surface of the pump column 10. The second electrical contact 22 faces diagonally upward. The contact surfaces of the first electrical contact 21 and the second electrical contact 22 are inclined. This configuration prevents air from stagnating or accumulating around the first electrical contact 21 and the second electrical contact 22, and prevents air from reacting with liquefied gases such as liquid hydrogen in the vicinity of the first electrical contact 21 and the second electrical contact 22.

[0097] The second electrical contact 22 is connected to the power cable 25. The power cable 25 extends through the side wall of the pump column 10 and is connected to a power source (not shown). As shown in Figure 36, the submersible pump 7 is lowered inside the pump column 10 by a lifting device (see reference numeral 31 in Figure 4), and the first electrical contact 21 is brought into contact with the second electrical contact 22. This establishes an electrical connection between the motor 7a of the submersible pump 7 and the power cable 25.

[0098] The embodiments described above are intended to enable persons with ordinary skill in the art to implement the present invention. Various modifications of the above embodiments can be made naturally by those skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments as well. Therefore, the present invention is not limited to the embodiments described, but is to be interpreted in the broadest sense according to the technical idea defined by the claims. [Industrial applicability]

[0099] The present invention can be used in power supply devices and power supply methods for supplying power to submersible pumps for transferring liquefied gases such as liquefied ammonia, liquefied natural gas (LNG), and liquid hydrogen. [Explanation of Symbols]

[0100] 1. Liquefied gas tank facilities 3. Liquefied gas storage tank 5 Pump System 6. Suction valve 7 Submersible pump 7a electric motor 10 Pump Column 12. Purge gas introduction port 13. Liquefied gas discharge port 14 Top lid 15 Power supply device 17 Suspension Cables 21 First electrical contact 21a 1st contact surface 22 Second electrical contact 22a 2nd contact surface 25 Power Cables 25A metal wiring 25B Power supply line 30 Positioning mechanism 30A Guide Rail 30B Guide Follower 41 First contact assembly 42 Second contact assembly 44 springs 45 Support structure 47 Base Bracket 48 Insulator 48a through hole 50 flange 54 Tapered surface 55 Reverse tapered surface 57 Lead wires 59 Electrical contact holder 60 Conductors 63 Multi-contact 74 springs 75 Support structure 77 Base Bracket 78 Insulator 78a through hole 84 Tapered surface 85 Reverse tapered surface 89 Electrical contact holder 93 Multi-contact 96 Pulley 97 Power supply connector 99 Power supply line 100A, 100B Electrical Connectors 105 Suspension Structure 107 Guide groove 111 Longitudinal extension structure 111a Through hole 112 Electrical contact holder 114 Guide Followers 120 electrode rails 121 Beam 123 Electrode Bar 130 base

Claims

1. A power supply device for supplying power to a submersible pump used for transferring liquefied gas, A first electrical contact fixed to the submersible pump and electrically connected to the electric motor of the submersible pump, A second electrical contact that contacts the first electrical contact, A power cable electrically connected to the second electrical contact, A positioning mechanism that determines the relative position of the first electrical contact and the second electrical contact in the circumferential direction of the submersible pump, A spring that presses the first electrical contact against the second electrical contact, The support structure comprises a support structure that movably supports the first electrical contact, There is a horizontal gap between the first electrical contact and the support structure. The positioning mechanism has a combination of a guide rail and a guide follower. The horizontal gap between the first electrical contact and the support structure is greater than the horizontal gap between the guide rail and the guide follower. A power supply device wherein at least a portion of the second electrical contact is located within the pump column that houses the submersible pump.

2. The power supply device according to claim 1, wherein the first electrical contact and the second electrical contact are in contact with each other and are movable relative to each other in the longitudinal direction of the pump column.

3. The power supply device according to claim 1, wherein the entirety of the second electrical contact is located within the pump column, and at least a portion of the power cable is located within the pump column.

4. The power supply device according to claim 1, wherein a portion of the second electrical contact is located outside the pump column, and the entire power cable is located outside the pump column.

5. The power supply device according to claim 1, wherein the power cable is fixed to the inner or outer surface of the pump column.

6. The power supply device according to claim 1, wherein the power cable has structural resistance to temperatures below the boiling point of the liquefied gas.

7. The first electrical contact has a tapered surface, The power supply device according to claim 1, wherein the second electrical contact has an inverse tapered surface shaped to conform to the tapered surface.

8. A power supply device for supplying power to a submersible pump used for transferring liquefied gas, A first electrical contact fixed to the submersible pump and electrically connected to the electric motor of the submersible pump, A second electrical contact that contacts the first electrical contact, A power cable electrically connected to the second electrical contact, A spring that presses the second electrical contact against the first electrical contact, A support structure that movably supports the second electrical contact, The submersible pump is equipped with a positioning mechanism that determines the relative positions of the first electrical contact and the second electrical contact in the circumferential direction, There is a horizontal gap between the second electrical contact and the support structure. The positioning mechanism has a combination of a guide rail and a guide follower. The horizontal gap between the second electrical contact and the support structure is greater than the horizontal gap between the guide rail and the guide follower. A power supply device wherein at least a portion of the second electrical contact is located within the pump column that houses the submersible pump.

9. The second electrical contact has a tapered surface, The power supply device according to claim 8, wherein the first electrical contact has an inverse tapered surface shaped to conform to the tapered surface.

10. A submersible pump for transferring liquefied gas, The pump column in which the aforementioned submersible pump is housed, A pump system comprising a power supply device according to any one of claims 1 to 9.

11. A liquefied gas storage tank for storing liquefied gas, A pump column is located inside the liquefied gas storage tank, A submersible pump for transferring the liquefied gas is located within the pump column, A liquefied gas tank facility comprising a power supply device according to any one of claims 1 to 9.

Images