Power cables for submersible pumps, pump delivery methods, pump retrieval methods

Abstract

To provide a power cable that can facilitate handling of a power cable connected to a submersible pump and achieves securing of safety for operators and reduction of loads on operators.SOLUTION: A power cable 36 for supplying power to a submersible pump 2 disposed in a pump column 3 to transport a liquefied gas includes: a plurality of divided power cables 36A; and a plurality of cable connectors 36B to which the plurality of divided power cables 36A are electrically connected.SELECTED DRAWING: Figure 1

Description

【Technical Field】 【0001】 The present invention relates to a power cable for supplying power to a submersible pump that boosts liquefied gases such as liquefied ammonia, liquefied natural gas (LNG), and liquid hydrogen. Furthermore, the present invention relates to a method of carrying a submersible pump into a pump column and a method of pulling a submersible pump out of a pump column using such a power cable. 【Background Art】 【0002】 Natural gas is widely used as a fuel for thermal power generation and as a chemical raw material. In addition, ammonia and hydrogen are expected as energy sources that do not generate carbon dioxide, which causes global warming. Examples of uses 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 room temperature, they are cooled and liquefied for storage and transportation. Liquefied gases such as liquefied natural gas (LNG), liquefied ammonia, and liquid hydrogen are once stored in a liquefied gas storage tank and then transferred to a power plant, factory, etc. by a pump. 【0003】 FIG. 19 is a schematic diagram showing a conventional example of a liquefied gas storage tank storing liquefied gas and a pump for pumping up the liquefied gas. A pump 500 is installed in a vertical pump column 505 installed in a liquefied gas storage tank 501. The upper end opening of the pump column 505 is closed by an upper lid 510. The inside of the pump column 505 is filled with liquefied gas, and the entire pump 500 is immersed in the liquefied gas. Therefore, the pump 500 is a submersible pump that can operate 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 through the pump column 505, and is discharged from the pump column 505 through a liquefied gas discharge port 509. 【0004】 The pump 500 is housed within the pump column 505 with a suspension cable 508 connected to its upper part. The upper part of the suspension cable 508 is wrapped 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 suspension cable 508 is connected to the pump 500. Therefore, the suspension cable 508, like the pump 500, is housed within the pump column 505. 【0005】 The suspension cable 508 is used when moving the pump 500 into the pump column 505 and when lifting the pump 500 out of the pump column 505. By keeping the suspension cable 508 connected to the pump 500, the work of connecting the suspension cable 508 to the pump 500 when lifting the pump 500 is eliminated. While the pump 500 is in operation, the suspension cable 508 is immersed in liquefied gas inside the pump column 505 together with the pump 500. 【0006】 Similarly, the power cable 507 is connected to the motor of the pump 500 and extends through the pump column 505 to outside the pump column 505. Power is supplied to the motor of the pump 500 through the power cable 507, thereby enabling the pump 500 to operate within the pump column 505. 【0007】 Figure 20 illustrates the process of moving the pump 500 into the pump column 505 and 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 suspension cable 508 is connected to the hoisting machine 513. The pump 500 is suspended from the suspension cable 508 and raised and lowered inside the pump column 505 by the hoisting machine 513. 【0008】 As the pump 500 rises and falls, the power cable 507 is also fed into the pump column 505 and pulled up from the pump column 505. [Prior art documents] [Patent Documents] 【0009】 [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] 【0010】 However, pump columns 505 for liquefied gas are generally very long vertically, sometimes reaching tens of meters. The power cable 507 connected to the pump 500 installed at the bottom of such a pump column 505 is also inevitably long. As a result, the operation of feeding the power cable 507 into and out of the pump column 505 becomes a very large-scale operation. In particular, when pulling the power cable 507 out of the pump column 505, the power cable 507, which has been in contact with the liquefied gas, is extremely cold, and handling the long power cable 507 is dangerous. 【0011】 Therefore, the present invention provides a power cable that can facilitate the handling of power cables connected to a submersible pump, thereby ensuring worker safety and reducing the burden on workers. Furthermore, the present invention provides a method for transporting a submersible pump into a pump column and a method for retrieving a submersible pump from a pump column using such a power cable. [Means for solving the problem] 【0012】 In one embodiment, a power cable is provided for supplying power to a submersible pump located in a pump column for transferring liquefied gas, the power cable comprising a plurality of segmented power cables and a plurality of cable connectors for electrically connecting the plurality of segmented power cables. 【0013】 In one embodiment, the length of each divided power cable is shorter than the length of the pump column. In one embodiment, each cable connector includes a female connector and a male connector connected to both ends of each divided power cable. In one embodiment, the plurality of cable connectors are each supported by a plurality of connecting links that connect a plurality of segmented suspension cables for suspending the submersible pump within the pump column. In one embodiment, the load of the plurality of divided power cables is supported by the plurality of divided suspension cables. 【0014】 One embodiment provides a method for introducing a submersible pump used for transferring liquefied gas into a pump column, wherein the submersible pump is lowered within the pump column by a suspension cable connected to a hoisting machine, and multiple divided power cables for supplying power to the submersible pump are connected one by one to the submersible pump using cable connectors. 【0015】 In one embodiment, the method further includes the steps of housing the submersible pump in a purge container and supplying purge gas into the purge container to expose the submersible pump to the purge gas. In one embodiment, the step of lowering the submersible pump within the pump column by the suspension cable connected to the hoisting machine is a step of lowering the submersible pump within the pump column by the multiple segmented suspension cables connected to the hoisting machine, while connecting the multiple segmented suspension cables one by one with connecting links. In one embodiment, the cable connector is supported by the connecting link. In one embodiment, the load of the plurality of divided power cables is supported by the plurality of divided suspension cables. 【0016】 In one embodiment, a method is provided for lifting a submersible pump used for transferring liquefied gas from a pump column, wherein the submersible pump is lifted from the pump column by a suspension cable connected to a hoisting machine, while a plurality of segmented power cables for supplying power to the submersible pump are removed one by one. 【0017】 In one embodiment, the method further includes the steps of moving the submersible pump from the pump column into a purge container and supplying purge gas into the purge container to expose the submersible pump to the purge gas. In one embodiment, the step of lifting the submersible pump from within the pump column using the suspension cable connected to the hoisting machine is a step of lifting the submersible pump from within the pump column using the suspension cable while removing one by one the multiple segmented suspension cables that make up the suspension cable connected to the hoisting machine. In one embodiment, the plurality of divided power cables are electrically connected by cable connectors, the plurality of divided suspension cables are connected by connecting links, and the cable connectors are supported by the connecting links. In one embodiment, the load of the plurality of divided power cables is supported by the plurality of divided suspension cables. [Effects of the Invention] 【0018】 According to the present invention, since a plurality of split power cables are used, the submersible pump can be carried into the pump column while adding these split power cables one by one. Furthermore, the submersible pump can be lifted from the pump column while removing the plurality of split power cables one by one. Since the worker does not need to handle a long (e.g., several tens of meters) power cable, the load on the worker can be reduced. In particular, the safety of the worker when pulling up an extremely low-temperature power cable from the pump column can be ensured. 【Brief Description of the Drawings】 【0019】 [Figure 1] It is a diagram showing an embodiment of a pump system for transferring liquefied gas. [Figure 2] FIG. 2(a) is a side view showing an embodiment of a connecting link, and FIG. 2(b) is a top view of the connecting link. [Figure 3] It is a side view showing a connecting link, a split suspension cable connected to the connecting link, and a split power cable attached to the connecting link. [Figure 4] It is a diagram showing a state in which two split suspension cables are connected to a connecting link and two split power cables are connected by a male connector and a female connector. [Figure 5] It is a top view showing another embodiment of the connecting link. [Figure 6] It is a cross-sectional view showing an embodiment of a head plate and a sealing link. [Figure 7] It is a diagram showing a pump system before carrying a submersible pump into a pump column and an embodiment of a lifting device used for carrying the submersible pump into the pump column. <着 [Figure 8] It is a perspective view showing an embodiment of a locking member. [Figure 9] It is a diagram for explaining an embodiment of a method for carrying a submersible pump into a pump column. [Figure 10] It is a diagram for explaining an embodiment of a method for carrying a submersible pump into a pump column. [Figure 11] This diagram illustrates one embodiment of a method for transporting a submersible pump into a pump column. [Figure 12] This diagram illustrates one embodiment of a method for transporting a submersible pump into a pump column. [Figure 13] This diagram illustrates one embodiment of a method for transporting a submersible pump into a pump column. [Figure 14] This diagram illustrates one embodiment of a method for transporting a submersible pump into a pump column. [Figure 15] This diagram illustrates one embodiment of a method for raising a submersible pump from a pump column. [Figure 16] This diagram illustrates one embodiment of a method for raising a submersible pump from a pump column. [Figure 17] This diagram illustrates one embodiment of a method for raising a submersible pump from a pump column. [Figure 18] This diagram illustrates one embodiment of a method for raising a submersible pump from a pump column. [Figure 19] 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 20] This diagram illustrates the process of moving a pump into a pump column and the process of removing a pump from a pump column. [Modes for carrying out the invention] 【0020】 Embodiments of the present invention will be described below with reference to the drawings. Figure 1 shows one embodiment of a pump system for transferring liquefied gases. Examples of liquefied gases transferred by the pump system shown in Figure 1 include liquefied ammonia, liquid hydrogen, liquid nitrogen, liquefied natural gas, liquefied ethylene gas, and liquefied petroleum gas. 【0021】 As shown in Figure 1, the pump system comprises a submersible pump 2 for transferring liquefied gas, a pump column 3 in which the submersible pump 2 is housed, a purge container 1 connected to the upper end of the pump column 3, a cover wall 10 fixed to the upper end of the purge container 1, and a top lid 12 that closes the upper opening of the cover wall 10. The pump column 3 is installed in a liquefied gas storage tank 5 in which the liquefied gas is stored. The pump column 3 is a hollow container extending vertically, with its upper part protruding upward from the liquefied gas storage tank 5. The purge container 1 is in communication with the pump column 3. The pump column 3 has a purge gas inlet port 8 and a discharge port 9. 【0022】 A suction valve 6 is provided at the bottom of the pump column 3. The submersible pump 2 is installed on the suction valve 6 of the pump column 3. The suction valve 6 has a valve body 6A that covers the lower opening of the pump column 3 and a plurality of springs 6B that bias the valve body 6A upward. When the submersible pump 2 is not placed on the valve body 6A, the valve body 6A is pressed against the lower end of the pump column 3 by the plurality of springs 6B, closing the lower opening of the pump column 3. When the submersible pump 2 is placed on the valve body 6A, the weight of the submersible pump 2 causes the valve body 6A to move downward against the force of the springs 6B, thereby opening the suction valve 6. The suction valve 6 may also be an actuator-driven valve (e.g., an electric valve). 【0023】 The purge container 1 is a device for exposing the submersible pump 2 to purge gas before it is brought into the pump column 3 and after it has been pulled up from the pump column 3. The purge container 1 is fixed to the upper end of the pump column 3. The purge container 1 is equipped with a purge gas inlet port 17 and a gas outlet port 18 that communicate with its internal space 15. The upper opening of the purge container 1 is covered by a head plate 20, and the lower opening of the purge container 1 can be closed by a gate valve 21. In this embodiment, the gate valve 21 is a manual type that is opened and closed by manually operating a handle 21a, but it may also be configured to be opened and closed electrically. 【0024】 The head plate 20 is detachably fixed to the upper end of the purge container 1. The suspension cable 23 and connecting structure 28 are suspended from a sealing link 30 fixed to the head plate 20. The suspension cable 23 includes a plurality of segmented suspension cables 23B and connecting links 24 that connect these segmented suspension cables 23B. The length of each segmented suspension cable 23B is shorter than the length of the pump column 3. The plurality of segmented suspension cables 23B are connected in series by the connecting links 24. 【0025】 The connecting structure 28 is attached to the submersible pump 2. The connecting structure 28 has a connecting link 33 at its upper end, which is connected to the lower end of the suspension cable 23. The specific configuration of the connecting structure 28 is not particularly limited and may include cables or rods. The suspension cable 23 and the connecting structure 28 extend vertically within the purge container 1 and the pump column 3. 【0026】 The head plate 20 is covered by a cover wall 10 and a top cover 12. An electrical terminal 35 is mounted on the top surface of the top cover 12. This electrical terminal 35 is connected to a power source (not shown). A power cable 36 for supplying power to the motor of the submersible pump 2 extends vertically through the pump column 3, the purge container 1, and the cover wall 10 along the suspension cable 23 and the connecting structure 28, and is electrically connected to the electrical terminal 35. The power cable 36 includes a plurality of segmented power cables 36A and a cable connector 36B that electrically connects these segmented power cables 36A. The length of each segmented power cable 36A is shorter than the length of the pump column 3. The plurality of segmented power cables 36A are connected in series by the cable connector 36B. 【0027】 During operation of the submersible pump 2, the purge gas introduction port 8, the purge gas inlet port 17, and the gas outlet port 18 are closed by valves (not shown), and the gate valve 21 is open. 【0028】 During operation of the submersible pump 2, liquefied gas in the liquefied gas storage tank 5 is introduced into the pump column 3 through the suction valve 6, filling the pump column 3 with liquefied gas. During operation of the submersible pump 2, the entire submersible pump 2 is immersed in the liquefied gas. Therefore, the submersible pump 2 is configured to operate in liquefied gas. The liquefied gas pressurized by the submersible pump 2 is transferred to the outside through the discharge port 9. 【0029】 Figure 2(a) is a side view showing one embodiment of a connecting link 24 for connecting multiple split suspension cables 23B, and Figure 2(b) is a top view of the connecting link 24. The connecting link 24 has two pin holes 24a into which connecting pins, described later, for connecting the split suspension cables 23B are inserted. These pin holes 24a are located at the top and bottom of the connecting link 24. The connecting link 24 has a flange portion 25 that protrudes laterally. The connecting link 24 has a cable passage 26 that penetrates the flange portion 25 in the vertical direction. The split power cable 36A is inserted into this cable passage 26. In this embodiment, the cable passage 26 has the shape of an outward-opening notch so that the split power cable 36A can be inserted into the cable passage 26 from the side of the connecting link 24. In other embodiments, the cable passage 26 may have the shape of a through hole. 【0030】 Figure 3 is a side view showing a connecting link 24, a divided suspension cable 23B connected to the connecting link 24, and a divided power cable 36A supported by the connecting link 24. Each divided suspension cable 23B has a connecting terminal 29 at its end, and this connecting terminal 29 has a through hole 29a through which a connecting pin 31 can pass. The connecting pin 31 is inserted into the through hole 29a of the connecting terminal 29 of each divided suspension cable 23B and into the pin hole 24a of the connecting link 24, thereby connecting each divided suspension cable 23B to the connecting link 24. 【0031】 The divided power cables 36A are electrically connected to each other by a cable connector 36B, which includes a female connector 37 and a male connector 38. The male connector 38 has a shape that allows it to be mated into the female connector 37. The female connector 37 is connected to the upper end of each divided power cable 36A, and the male connector 38 is connected to the lower end of each divided power cable 36A. The divided power cables 36A have a width smaller than the cable passage 26, but the female connector 37 has a width larger than the cable passage 26, so the female connector 37 cannot pass through the cable passage 26. Therefore, the female connector 37 also functions as a stopper to prevent the divided power cables 36A from falling from the connecting link 24. In other words, the divided power cables 36A are supported by the connecting link 24 via the female connector 37. Therefore, the load of the divided power cables 36A connected to the female connector 37 is supported by the divided suspension cables 23B connected to the connecting link 24. 【0032】 If the male connector 38 has a width greater than the width of the cable passage 26, the male connector 38 may be connected to the upper end of the divided power cable 36A and the female connector 37 may be connected to the lower end of the divided power cable 36A. In this case, the male connector 38 functions as a stopper to prevent the divided power cable 36A from falling from the connecting link 24. 【0033】 Figure 4 shows a configuration in which two split suspension cables 23B are connected to a connecting link 24, and two split power cables 36A are connected by a male connector 38 and a female connector 37. As shown in Figure 4, the male connector 38 connected to the upper split power cable 36A is inserted into the female connector 37 connected to the lower split power cable 36A, thereby connecting the male connector 38 and the female connector 37 and establishing an electrical connection between the upper and lower split power cables 36A. The male connector 38 and the female connector 37 are supported by the connecting link 24. Furthermore, the connecting link 24 can support the load of the lower split power cable 36A, thus preventing unintended disconnection of the male connector 38 and the female connector 37. 【0034】 Each divided power cable 36A may be divided into three divided power cables for three-phase AC. In that case, as shown in Figure 5, each connecting link 24 may have three cable passages 26 into which the three divided power cables for three-phase AC are inserted. 【0035】 Figure 6 is a cross-sectional view showing one embodiment of the head plate 20 and sealing link 30. The head plate 20 includes a plate body 40 shaped to cover the upper opening of the purge container 1, a projection 41 extending upward from the plate body 40, a movable flange 42 surrounding the projection 41, and a seal 44 (e.g., gland packing) that seals the gap between the outer surface of the projection 41 and the inner surface of the movable flange 42. The projection 41 and the movable flange 42 have a cylindrical shape. The movable flange 42 is movable vertically relative to the projection 41 and the plate body 40. The head plate 20 includes cable ports 47 fixed to both sides of the plate body 40. Each cable port 47 has a hole (not shown) through which a suspension cable 23 can pass. 【0036】 The head plate 20 has a through hole 50 formed in the protruding portion 41. This through hole 50 extends vertically. The width of the through hole 50 is greater than the width of the suspension cable 23 and the upper part of the connecting structure 28 (see Figure 1), allowing the upper part of the connecting structure 28 (including the connecting link 33) and the suspension cable 23 (including the connecting link 24) to pass through the through hole 50. The head plate 20 is removably fixed to the upper end of the purge container 1 by fasteners 53 such as bolts and nuts. The sealing link 30 is removably fixed to the movable flange 42 by fasteners such as screws (not shown). The upper end of the through hole 50 is closed by the sealing link 30. The power cable 36 extends through the sealing link 30. The divided suspension cable 23B and the power cable 36 that constitute the suspension cable 23 extend through the through hole 50. 【0037】 Next, one embodiment of a method for moving the submersible pump 2 into the pump column 3 will be described. Figure 7 shows the pump system before moving the submersible pump 2 into the pump column 3, and one embodiment of the lifting device 60 used to move the submersible pump 2 into the pump column 3. The cover wall 10 and the top cover 12 are removed before moving the submersible pump 2 into the pump column 3. The gate valve 21 is closed. 【0038】 The lifting device 60 includes a hoisting machine 61 such as a hoist or winch, the suspension cable 23 connected to the hoisting machine 61, the connecting structure 28 extending upward from the submersible pump 2, the head plate 20 positioned above the submersible pump 2 and having a shape that covers the upper opening of the purge container 1, and a locking member 65 that locks the connecting structure 28 to the head plate 20. The hoisting machine 61 is positioned above the pump column 3 and the purge container 1. 【0039】 The lower end of the connecting structure 28 is connected to the submersible pump 2, and the upper end of the connecting structure 28 is made up of a connecting link 33. Since this connecting link 33 has the same configuration as the connecting link 24 described with reference to Figures 2 to 4 or Figure 5, a redundant explanation will be omitted. 【0040】 The connecting link 33 has a flange portion 33a that protrudes laterally. The locking member 65 engages with the flange portion 33a of the connecting link 33. The divided power cable 36A extends through a cable passage (not shown) formed in the flange portion 33a of the connecting link 33, and the female connector 37 connected to the upper end of the divided power cable 36A is locked to the flange portion 33a. The cable passage (not shown) of the connecting link 33 has the same configuration as the cable passage 26 of the connecting link 24, which was described with reference to Figures 2 to 5, so a redundant explanation is omitted. 【0041】 The connecting link 33 extends through the locking member 65 and is supported by the locking member 65. The locking member 65 is placed on the head plate 20. More specifically, the locking member 65 is positioned to cover a portion of the through-hole 50 in the head plate 20. The connecting structure 28 and the split power cable 36A extend through the through-hole 50. 【0042】 Figure 8 is a perspective view showing one embodiment of the locking member 65. In this embodiment, the locking member 65 has a shape that engages with the connecting links 24, 33 (see Figure 1). The locking member 65 of this embodiment has an opening 66 in its center and is divided into a plurality of members 65A, 65A. The opening 66 is sized not to allow the passage of the connecting links 24, 33 (see Figure 1). 【0043】 In this embodiment, the locking member 65, which functions as a stopper for the connecting links 24, 33, is a split ring (e.g., a two-part ring) consisting of multiple (typically two) members. However, the configuration of the connecting links 24, 33 and the locking member 65 is not limited to this embodiment, as long as they can perform their intended functions. For example, the locking member 65 may be a single member (e.g., a U-shaped member) having a notch extending outward from its center. Furthermore, the connecting links 24, 33 may be structures such as shackles. In other examples, the connecting links 24, 33 may have horizontally extending through holes instead of laterally protruding portions, and the locking member 65 may be a rod-shaped member inserted into the through hole. 【0044】 Returning to Figure 7, the width of the locking member 65 is greater than the width of the through-hole 50 in the head plate 20, and the locking member 65 cannot pass through this through-hole 50. On the other hand, the width of the connecting link 33 is smaller than the width of the through-hole 50 in the head plate 20, and the connecting link 33 can pass through the through-hole 50. However, as long as the connecting link 33 is supported by the locking member 65, the connecting link 33 cannot pass through the through-hole 50. Therefore, the submersible pump 2 is suspended from the locking member 65 on the head plate 20 by the connecting structure 28, which includes the connecting link 33. The load of the submersible pump 2 is supported by the head plate 20 via the connecting structure 28, which includes the connecting link 33, and the locking member 65. The split power cable 36A extends along the connecting structure 28, and the female connector 37 connected to the split power cable 36A is supported on the connecting link 33. 【0045】 Before the submersible pump 2 is introduced into the purge vessel 1, a purge gas supply line 71 extending from a purge gas supply source 70 is connected to the purge gas inlet port 17, and a vacuum line 74 is connected to the gas outlet port 18. The vacuum line 74 is connected to a vacuum source (not shown), such as a vacuum pump. Examples of purge gas supply sources 70 include a nitrogen gas supply source, a helium gas supply source, a hydrogen gas supply source, or a combination thereof. In one embodiment, the purge gas supply source 70 may include multiple purge gas supply sources of different types, for example, at least two of a nitrogen gas supply source, a helium gas supply source, and a hydrogen gas supply source. In this case, the multiple purge gas supply sources may be selectively connected to the purge gas supply line 71. 【0046】 Figures 9 to 14 illustrate one embodiment of a method for transporting the submersible pump 2 into the pump column 3. The series of operations shown in Figures 9 to 14 include drying out the submersible pump 2 by exposing it to purge gas in the purge container 1, lowering the submersible pump 2 inside the pump column 3, adding the multiple divided suspension cables 23B one by one to the suspension cable 23, and adding the multiple divided power cables 36A one by one to the power cable 36. 【0047】 Prior to the loading operation described below, liquefied gas is discharged from the pump column 3. Specifically, purge gas is supplied into the pump column 3 from the purge gas supply line 71 and / or the purge gas introduction port 8, and the pressure of the purge gas discharges the liquefied gas from the pump column 3 through the suction valve 6. 【0048】 In step 101, the suspension cable 23 connected to the hoisting machine 61 is connected to the head plate 20. More specifically, the suspension cable 23 is connected to the cable port 47 of the head plate 20. The submersible pump 2 is suspended from the head plate 20 by a connecting structure 28 including a connecting link 33 and a locking member 65. One of the multiple divided power cables 36A is connected to the motor of the submersible pump 2, and the female connector 37 at the upper end of the divided power cable 36A is locked to the connecting link 33. 【0049】 In step 102, the hoisting machine 61 lowers the submersible pump 2, head plate 20, connecting structure 28, divided power cable 36A, and locking member 65 together, so that the head plate 20 covers the upper opening of the purge container 1. The head plate 20 is fixed to the upper end of the purge container 1 by fasteners 53 as shown in Figure 6. 【0050】 In step 103, the suspension cable (first suspension cable) 23A connected to the hoisting machine 61 is disconnected from the cable port 47. Furthermore, one of the pre-prepared divided suspension cables (second suspension cables) 23B is added to the suspension cable 23. More specifically, the upper end of the newly added divided suspension cable 23B is connected to the suspension cable 23A connected to the hoisting machine 61 via a connecting link 24, and the lower end of the newly added divided suspension cable 23B is connected to a connecting link 33 of the connecting structure 28. In this embodiment, the suspension cable 23 includes the first suspension cable 23A extending from the hoisting machine 61 and a plurality of divided suspension cables (second suspension cables) 23B that can be disconnected from the first suspension cable 23A. 【0051】 Similarly, one of the pre-prepared divided power cables 36A is added to the power cable 36. More specifically, the newly added divided power cable 36A is passed through the cable passage 26 of the connecting link 24 (see Figure 2), and the female connector 37 attached to the divided power cable 36A is placed on the connecting link 24. Furthermore, the male connector 38 attached to the newly added divided power cable 36A is connected to the female connector 37 on the already installed divided power cable 36A. In this way, the newly added divided power cable 36A is electrically connected to the existing divided power cable 36A. Multiple divided power cables 36A that are electrically connected in this manner constitute the power cable 36. 【0052】 With the upper opening of the purge container 1 covered by the head plate 20 and the lower opening of the purge container 1 closed by the gate valve 21, the internal space 15 of the purge container 1, which houses the submersible pump 2, is evacuated through the gas outlet port 18. Then, purge gas (for example, including an inert gas and / or a gas consisting of the same components as the liquefied gas) is supplied to the internal space 15 from the purge gas inlet port 17, filling the internal space 15 with purge gas. The submersible pump 2 is exposed to (contacted by) the purge gas inside the purge container 1, thereby removing air and moisture from the surface of the submersible pump 2. This process is a dry-up that removes air and moisture from the submersible pump 2. The evacuation of the internal space 15 and the supply of purge gas to the internal space 15 may be repeated. 【0053】 The purge gas used is a gas composed of components with a boiling point lower than or equal to the boiling point of the liquefied gas being pumped up by the submersible pump 2. This is to prevent the purge gas from liquefying when it comes into contact with the liquefied gas. Examples of purge gases include inert gases such as nitrogen gas and helium gas. For example, if the liquefied gas being pumped up by the submersible pump 2 is liquefied natural gas, nitrogen gas, which has a boiling point (-196°C) lower than the boiling point of liquefied natural gas (-162°C), is used as the purge gas. In another example, if the liquefied gas being pumped up by the submersible pump 2 is liquid hydrogen, helium gas, which has a boiling point (-269°C) lower than the boiling point of hydrogen (-253°C), is used as the purge gas. 【0054】 A portion of the purge gas may consist of the same components as the liquefied gas. If the gas outlet port 18 is connected to a gas treatment device, all of the purge gas may consist of the same components as the liquefied gas. For example, if the liquefied gas is liquid hydrogen, a portion or all of the purge gas may be hydrogen gas. In another example, if the liquefied gas is liquefied ammonia, a portion or all of the purge gas may be ammonia gas. 【0055】 In step 104, the hoisting machine 61 slightly lifts the suspension cable 23, the split power cable 36A, and the submersible pump 2, and removes the locking member 65 from the head plate 20. The load of the submersible pump 2 is supported by the hoisting machine 61. To prevent air from entering through the through-hole 50 in the head plate 20, the supply of purge gas into the purge container 1 through the purge gas inlet port 17 continues. Meanwhile, the vacuuming of the internal space 15 of the purge container 1 through the gas outlet port 18 is stopped. Furthermore, the gate valve 21 is opened. 【0056】 In step 105, the hoisting machine 61 further lowers the suspension cable 23, the split power cable 36A, the connecting structure 28, and the submersible pump 2. While the submersible pump 2 is being lowered, purge gas may be supplied into the pump column 3 from the purge gas introduction port 8. The locking member 65 is placed back on the head plate 20 before the uppermost connecting link 24 enters the purge container 1. As the submersible pump 2 is lowered, the split suspension cable 23B and the split power cable 36A extend through the through-hole 50 in the head plate 20. 【0057】 In step 106, the suspension cable 23, the divided power cable 36A, the connecting structure 28, and the submersible pump 2 are lowered by the hoisting machine 61 until the connecting link 24, which is connected to the upper end of the divided suspension cable 23B, engages with (contacts) the locking member 65. Once the connecting link 24 engages with the locking member 65, the load of the submersible pump 2 is supported by the locking member 65 and the head plate 20. 【0058】 Then, until the submersible pump 2 approaches the bottom of the pump column 3, the same steps as in steps 103 to 106 above are repeated, adding (connecting) the remaining segments of the multiple segmented suspension cables 23B one by one, and connecting the remaining segments of the multiple segmented power cables 36A one by one with cable connectors 36B. The load of the multiple segmented power cables 36A connected by cable connectors 36B, including female connectors 37 and male connectors 38, is supported by the multiple segmented suspension cables 23B via connecting links 24. While the submersible pump 2 is being lowered, purge gas is supplied into the pump column 3 from the purge gas inlet port 17 and / or the purge gas introduction port 8. 【0059】 In step 107, as the submersible pump 2 approaches the bottom of the pump column 3, the last segmented suspension cable 23B is added to the suspension cable 23, and the last segmented power cable 36A is added to the power cable 36. The upper end of this last segmented suspension cable 23B is connected to the sealing link 30, as described with reference to Figure 6. The lower end of the segmented power cable 36A is connected to the male connector 38, and the upper part of the segmented power cable 36A extends through the sealing link 30. In step 108, the locking member 65 is removed from the head plate 20, and then the submersible pump 2 is lowered until the sealing link 30 reaches a position directly above the head plate 20. The submersible pump 2 is positioned in a predetermined location directly above the suction valve 6 in the pump column 3. In step 109, the movable flange 42 of the head plate 20 is lifted upward and fixed to the sealing link 30 with fasteners such as screws (not shown). 【0060】 In step 110, the sealing link 30, the movable flange 42, and the submersible pump 2 are lowered until the sealing link 30 contacts the head plate 20. The submersible pump 2 is placed on the suction valve 6. The suction valve 6 opens due to the weight of the submersible pump 2. In step 111, the suspension cable 23A is disconnected from the sealing link 30, and then the cover wall 10 is secured to the upper end of the purge container 1. The uppermost split power cable 36A is connected to the electrical terminal 35 located on the upper surface of the top cover 12, and then the top cover 12 is secured to the cover wall 10. 【0061】 According to this embodiment, since multiple divided power cables 36A are used, the submersible pump 2 can be brought into the pump column 3 by adding (connecting) these divided power cables 36A one by one. Since workers do not need to handle long power cables (for example, several tens of meters), the workload on the workers can be reduced. 【0062】 Furthermore, in this embodiment, since multiple segmented suspension cables 23B are used, the submersible pump 2 can be brought into the pump column 3 by adding (connecting) these segmented suspension cables 23B one by one. Since workers do not need to handle long suspension cables (for example, several tens of meters), the burden on the workers can be reduced. 【0063】 Next, an embodiment of a method for raising the submersible pump 2 from the pump column 3 will be described with reference to Figures 15 to 18. In raising the submersible pump 2, the steps described with reference to Figures 9 to 14 are basically performed in the reverse order. The series of operations shown in Figures 15 to 18 include raising the submersible pump 2 within the pump column 3, removing the multiple divided suspension cables 23B one by one, removing the multiple divided power cables 36A one by one, and a hot-up operation in which the submersible pump 2 is exposed to purge gas in the purge container 1. 【0064】 In step 201, the top cover 12 is removed from the cover wall 10, and the uppermost divided power cable 36A is disconnected from the electrical terminal 35. Furthermore, the cover wall 10 is removed from the purge container 1. Subsequently, the suspension cable 23A is connected to the sealing link 30, thereby connecting the suspension cable 23A via the sealing link 30 to the suspension cable 23B extending from the connecting structure 28 which is connected to the submersible pump 2. The hoisting machine 61 slightly lifts the sealing link 30, the movable flange 42, the suspension cable 23B, the divided power cable 36A, the connecting structure 28, and the submersible pump 2, and closes the suction valve 6. Furthermore, purge gas is supplied into the purge container 1 and the pump column 3 through the purge gas inlet port 17. The pressure inside the pump column 3 rises, and the suction valve 6 opens accordingly. This causes the liquefied gas to be discharged from the pump column 3 through the suction valve 6. 【0065】 In step 202, the movable flange 42 is detached from the sealing link 30. Furthermore, the multiple segmented suspension cables 23B, the multiple segmented power cables 36A, the connecting structure 28, and the submersible pump 2 are hoisted up by the hoist 61 until the entire uppermost segmented suspension cable 23B and the entire uppermost segmented power cable 36A are positioned above the purge container 1. The locking member 65 is then placed on the head plate 20. As the submersible pump 2 is hoisted up, the suspension cables 23B and segmented power cables 36A extend through the through-holes 50 in the head plate 20. 【0066】 In step 203, the hoisting machine 61 slightly lowers the divided suspension cable 23B, divided power cable 36A, connecting structure 28, and submersible pump 2 until the connecting link 24, which is directly above the locking member 65, engages (contacts) with the locking member 65. The load of the submersible pump 2 is supported by the locking member 65 and the head plate 20. 【0067】 In step 204, the uppermost split suspension cable 23B located outside the purge container 1 is detached from the suspension cable 23. The sealing link 30 is detached from the suspension cable 23 along with the split suspension cable 23B. The uppermost split power cable 36A is also detached from the power cable 36. At this time, the male connector 38 connected to the lower end of the split power cable 36A is detached from the female connector 37 on the connecting link 24, which is supported by the locking member 65. 【0068】 In step 205, the suspension cable 23A extending from the hoisting machine 61 is connected to the connecting link 24 which is engaged with the locking member 65. This reconnects the suspension cable 23A to the submersible pump 2 via the split suspension cable 23B. Then, the same steps as those described in steps 202 to 205 above are repeated, one by one, while disconnecting the multiple divided suspension cables 23B and one by one, while disconnecting the multiple divided power cables 36A, until the submersible pump 2 is raised into the purge container 1 by the hoisting machine 61. While the submersible pump 2 is being raised, purge gas is supplied into the pump column 3 from the purge gas inlet port 17 and / or the purge gas introduction port 8. 【0069】 In step 206, with the submersible pump 2 located inside the purge container 1, the gate valve 21 is closed. With the upper opening of the purge container 1 covered by the head plate 20 and the lower opening of the purge container 1 closed by the gate valve 21, purge gas (for example, including an inert gas and / or a gas consisting of the same components as the liquefied gas) is supplied to the internal space 15 from the purge gas inlet port 17, filling the internal space 15 with purge gas. The submersible pump 2 is exposed to (contacted by) the purge gas inside the purge container 1, thereby heating the submersible pump 2. This step is a hot-up to heat the submersible pump 2. 【0070】 In step 207, the fasteners 53 (see Figure 6), such as bolts and nuts, that secure the head plate 20 to the purge container 1 are removed. Then, the suspension cable 23A is connected to the cable port 47 of the head plate 20. Next, the hoisting machine 61 raises the head plate 20, the connecting structure 28, the lowest divided power cable 36A, the locking member 65, and the submersible pump 2 as a single unit, moving the submersible pump 2 outside the purge container 1. 【0071】 According to this embodiment, since multiple divided power cables 36A are used, the submersible pump 2 can be pulled up from the pump column 3 while removing (disconnecting) these divided power cables 36A one by one. Since workers do not need to handle long power cables (for example, tens of meters), the burden on the workers can be reduced. In particular, the safety of the workers can be ensured when pulling up the cryogenic power cable 36 from the pump column 3. 【0072】 Furthermore, according to this embodiment, since multiple segmented suspension cables 23B are used, the submersible pump 2 can be lifted from the pump column 3 while removing (disconnecting) these segmented suspension cables 23B one by one. Since workers do not need to handle long suspension cables (for example, several tens of meters), the burden on the workers can be reduced. In particular, the safety of the workers can be ensured when lifting the cryogenic suspension cable 23 from the pump column 3. 【0073】 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. [Explanation of symbols] 【0074】 1. Purge container 2 Submersible pump 3 Pump Column 5. Liquefied gas storage tank 6. Suction valve 8. Purge gas introduction port 9 Discharge Ports 10 Cover Wall 12 Top lid 15 Interior space 17. Purge gas inlet port 18 Gas outlet ports 20 Headplates 21 Gate valve 23 Suspension Cables 23A First suspension cable 23B Split suspension cable (second suspension cable) 24 Linking Links 24a Pinhole 25 Flange section 26 Cableway 28 Connected structure 29 Connecting terminals 30 Sealed Links 31 Connecting pins 33 Linking Links 33a Flange section 35 Electrical terminals 36 Power Cables 36A Split Power Cable 36B Cable Connector 37 Female connector 38 Male Connectors 40 Plate Body 41 Protrusion 42 Movable flange 44 stickers 47 Cable Ports 50 through holes 53 Fasteners 60 Lifting device 61. Winding machine 65 Locking member 66 Aperture 70. Purge gas supply source 71 Purge gas supply line 74 Vacuum Line

Claims

[Claim 1] A power cable for supplying power to a submersible pump located inside a pump column for transferring liquefied gas, Multiple divided power cables, It is equipped with multiple cable connectors that electrically connect the multiple divided power cables, A power cable in which the plurality of cable connectors are each supported by a plurality of connecting links that connect a plurality of segmented suspension cables for suspending the submersible pump within the pump column. [Claim 2] The power cable according to claim 1, wherein the length of each divided power cable is shorter than the length of the pump column. [Claim 3] The power cable according to claim 1 or 2, wherein each cable connector comprises a female connector and a male connector connected to both ends of each divided power cable. [Claim 4] The power cable according to claim 1, wherein the load of the plurality of divided power cables is supported by the plurality of divided suspension cables. [Claim 5] A method for introducing a submersible pump used for transferring liquefied gas into a pump column, The submersible pump is lowered within the pump column by a suspension cable connected to the hoisting machine, while multiple divided power cables for supplying power to the submersible pump are connected one by one by cable connectors. The process of lowering the submersible pump within the pump column by the suspension cable connected to the hoisting machine is a process of lowering the submersible pump within the pump column by the multiple segmented suspension cables connected to the hoisting machine, while connecting each of the multiple segmented suspension cables one by one with connecting links. A method wherein the cable connector is supported by the connecting link. [Claim 6] The aforementioned submersible pump is housed in a purge container, The method according to claim 5, further comprising the step of supplying purge gas into the purge container and exposing the submersible pump to the purge gas. [Claim 7] The method according to claim 5, wherein the load of the plurality of divided power cables is supported by the plurality of divided suspension cables. [Claim 8] A method for lifting a submersible pump used for transferring liquefied gas from a pump column, While the submersible pump is being pulled up within the pump column by a suspension cable connected to the hoisting machine, the multiple divided power cables that supply power to the submersible pump are removed one by one. The step of lifting the submersible pump from within the pump column using the suspension cable connected to the hoisting machine is a step of lifting the submersible pump from within the pump column using the suspension cable while removing one by one the multiple segmented suspension cables that make up the suspension cable connected to the hoisting machine, The aforementioned multiple divided power cables are electrically connected by cable connectors. The aforementioned multiple segmented suspension cables are connected by connecting links. A method wherein the cable connector is supported by the connecting link. [Claim 9] The submersible pump is moved from the pump column into the purge container. The method according to claim 8, further comprising the step of supplying purge gas into the purge container and exposing the submersible pump to the purge gas. [Claim 10] The method according to claim 8, wherein the load of the plurality of divided power cables is supported by the plurality of divided suspension cables.

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