Pump system, pump carrying-in method, and pump lifting method

Abstract

To provide a pump system capable of suppressing a rise in a liquid level of liquefied gas in a pump column during operation of a pump.SOLUTION: A pump system comprises: a pump 2 for pressurizing liquefied gas; a pump column 3 in the inside of which the pump 2 is disposed; a purge container 1 connected to the pump column 3; an electric power cable 36 extending in the pump column 3 and the purge container 1 and connected to the pump 2; a hanging structure 23 including a plurality of split suspension pipes 23B that extend in the pump column 3 and the purge container 1 and are connected to the pump 2; and a discharge pipe 34 extending in the pump column 3 and the purge container 1 and connected to a discharge port 2a of the pump 2. The plurality of split suspension pipes 23B are connected in a row and are configured to be detachable from one another, and at least a part of the discharge pipe 34 is composed of a flexible pipe configured to be bendable.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pump system including a pump for pressurizing a liquefied gas such as liquefied ammonia, liquefied natural gas (LNG), liquid hydrogen, etc. The present invention also relates to a method for loading the pump into a pump column and a method for lifting the pump out of the pump column. [Background technology]

[0002] Natural gas is widely used for thermal power generation and as a chemical raw material. Ammonia and hydrogen are also expected to be 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. Natural gas, ammonia, and hydrogen are in a gaseous state at room temperature, so they are cooled and liquefied in order to be stored and transported. Liquefied gases such as liquefied natural gas (LNG), liquefied ammonia, and liquefied hydrogen are temporarily stored in liquefied gas tanks and then transported to power plants, factories, etc. by pumps.

[0003] 34 is a schematic diagram showing a liquefied gas tank in which liquefied gas is stored, and a conventional example of a pump for pumping up the liquefied gas. When pump 500 is operated, liquefied gas in liquefied gas tank 501 is sucked into pump column 505, rises inside pump column 505, and is discharged from pump column 505 through liquefied gas discharge port 509. Pump column 505 is provided with purge gas introduction port 512. This purge gas introduction port 512 is closed when pump 500 is operating.

[0004] 35 is a diagram for explaining the operation of loading the pump 500 into the pump column 505 and the operation of removing the pump 500 from the pump column 505. When installing the pump 500 in the pump column 505 and when removing the pump 500 from the pump column 505 for the purpose of maintenance or the like, the top cover 510 is removed and the cable 508 is connected to a hoist 513. The pump 500 is suspended from the cable 508 and is raised or lowered within the pump column 505 by the hoist 513.

[0005] During loading and unloading of the pump 500, a purge gas is introduced into the pump column 505 through a purge gas introduction port 512 in order to prevent ambient air from entering the pump column 505. The purge gas introduced into the pump column 505 is discharged from an upper opening of the pump column 505. An inert gas such as N2 gas or He gas is used as the purge gas. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 49-4407 [Patent Document 2] Special Publication No. 56-66484 [Patent Document 3] Japanese Utility Model Application Publication No. 64-32400 Summary of the Invention [Problem to be solved by the invention]

[0007] However, since the upper opening of the pump column 505 is larger than the width of the pump 500, a large amount of purge gas is required to prevent air from entering the pump column 505. In particular, He gas is expensive, which increases the cost of transporting the pump 500 in and out.

[0008] One possible solution to this problem is to provide a gate valve that separates the inside and outside of the pump column 505. However, when the pump 500 is in operation, the gate valve is in contact with the cryogenic liquefied gas pumped up by the pump 500 for a long period of time, which may cause the gate valve to be damaged.

[0009] Furthermore, while the pump 500 is in operation, the liquefied gas rises inside the pump column 505 and exceeds the liquid level inside the liquefied gas storage tank 501. As a result, the upper part of the pump column 505, which is under the atmosphere, is cooled by the liquefied gas, and oxygen in the air may condense on the outer surface of the pump column 505. Liquid oxygen has a high combustion oxidizing property and may explode if it comes into contact with fire.

[0010] Therefore, the present invention provides a pump system capable of suppressing a rise in the liquid level of liquefied gas in a pump column during operation of the pump. The present invention also provides a method for loading such a pump into a pump column and a method for lifting the pump out of the pump column. [Means for solving the problem]

[0011] In one aspect, a pump system is provided comprising: a pump for pressurizing liquefied gas; a pump column in which the pump is disposed; a purge container connected to the pump column; a power cable extending through the pump column and the purge container and connected to the pump; a suspension structure including a plurality of split suspension pipes extending through the pump column and the purge container and connected to the pump; and a discharge pipe extending through the pump column and the purge container and connected to an outlet of the pump, wherein the plurality of split suspension pipes are connected in a row and configured to be detachable from one another, and at least a portion of the discharge pipe is composed of a flexible pipe configured to be bendable.

[0012] In one aspect, the discharge pipe is located outside the hanging structure. In one aspect, the discharge pipe is disposed within the hanging structure. In one embodiment, the system further includes a flow path switching device disposed within the hanging structure and connected to the pump outlet and the discharge pipe, the flow path switching device including a flow path structure having a first flow path, a second flow path, and a third flow path, and a valve body disposed within the flow path structure for selectively connecting the third flow path to either the first flow path or the second flow path, the first flow path being connected to the pump outlet, the second flow path being connected to the interior of the hanging structure, and the third flow path being connected to the discharge pipe. In one aspect, the power cable is disposed within the suspension structure. In one aspect, the pump system further comprises a gate valve disposed between the pump column and the purge reservoir. In one aspect, the pump system further includes a head plate shaped to cover an upper opening of the purge container, and the uppermost split suspension pipe among the plurality of split suspension pipes is connected to the head plate.

[0013] In one aspect, a method for loading a pump used to transport liquefied gas into a pump column includes connecting a hanging structure connected to a lifting device to the pump, the hanging structure including at least one of a plurality of pre-prepared divided hanging tubes, and lowering the pump and the hanging structure within the pump column and a purge container by the lifting device while connecting the remaining plurality of divided hanging tubes one by one to the hanging structure, the purge container being connected to the pump column, and lowering a discharge pipe and a power cable connected to the pump within the pump column and the purge container while lowering the pump and the hanging structure within the pump column and the purge container, and at least a portion of the discharge pipe is composed of a flexible pipe configured to be bendable.

[0014] In one aspect, the discharge pipe is located outside the hanging structure. In one aspect, the discharge pipe is disposed within the hanging structure. In one aspect, the power cable is disposed within the suspension structure. In one aspect, the method further includes providing a purge gas within the discharge line and the hanging structure.

[0015] In one aspect, a method for lifting a pump used to transport liquefied gas from a pump column is provided, the method comprising: lifting the pump and the hanging structure within the pump column and a purge vessel by a lifting device while disconnecting a plurality of split hanging tubes one by one from a hanging structure connected to the pump, the hanging structure including the plurality of split hanging tubes connected in series, the purge vessel being connected to the pump column; and while lifting the pump and the hanging structure within the pump column and the purge vessel, lifting a discharge pipe and a power cable connected to the pump within the pump column and the purge vessel, wherein at least a portion of the discharge pipe is comprised of a flexible pipe configured to be bendable.

[0016] In one aspect, the discharge pipe is located outside the hanging structure. In one aspect, the discharge pipe is disposed within the hanging structure. In one aspect, the power cable is disposed within the suspension structure. Effect of the Invention

[0017] According to the present invention, the liquefied gas pressurized by the pump is discharged through a discharge pipe extending through the pump column and the purge container. Therefore, while the pump is in operation, the liquid level of the liquefied gas in the pump column is prevented from rising above the pump column. As a result, the liquefied gas is prevented from contacting components such as the purge container that are located above the pump column. [Brief description of the drawings]

[0018] [Figure 1]FIG. 1 illustrates one embodiment of a pump system for transporting liquefied gas. [Diagram 2] FIG. 2 is a close-up view of one embodiment of a portion of a suspension structure. [Diagram 3] FIG. 13 is a cross-sectional view of one embodiment of a head plate, a cover wall, and a top cover. [Figure 4] 13A-13C illustrate an embodiment of a locking member used when loading and unloading a pump into and from a pump column. [Diagram 5] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 6] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 7] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 8] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 9] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 10] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 11] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 12] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 13] 1A-1C illustrate an embodiment of a method for lifting a pump from a pump column. [Figure 14] 1A-1C illustrate an embodiment of a method for lifting a pump from a pump column. [Figure 15] 1A-1C illustrate an embodiment of a method for lifting a pump from a pump column. [Figure 16] 1A-1C illustrate an embodiment of a method for lifting a pump from a pump column. [Figure 17]1A-1C illustrate an embodiment of a method for lifting a pump from a pump column. [Figure 18] FIG. 13 illustrates another embodiment of a pump system. [Figure 19] FIG. 2 is a cross-sectional view showing a detailed configuration of a flow path switching device according to an embodiment. [Figure 20] FIG. 2 is a cross-sectional view showing a detailed configuration of a flow path switching device according to an embodiment. [Figure 21] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 22] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 23] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 24] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Diagram 25] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 26] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 27] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 28] 1A-1C are diagrams illustrating one embodiment of a method for loading a pump into a pump column. [Figure 29] 1A-1C illustrate an embodiment of a method for lifting a pump from a pump column. [Diagram 30] 1A-1C illustrate an embodiment of a method for lifting a pump from a pump column. [Diagram 31] 1A-1C illustrate an embodiment of a method for lifting a pump from a pump column. [Diagram 32] 1A-1C illustrate an embodiment of a method for lifting a pump from a pump column. [Diagram 33] 1A-1C illustrate an embodiment of a method for lifting a pump from a pump column. [Diagram 34] 1 is a schematic diagram showing a conventional example of a liquefied gas storage tank in which liquefied gas is stored and a pump for pumping up the liquefied gas. [Diagram 35] 10A to 10C are diagrams illustrating an operation of loading a pump into a pump column and an operation of loading a pump out of the pump column. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a diagram showing one embodiment of a pump system for transporting liquefied gas. Examples of liquefied gas that may be transported by the pump system shown in Fig. 1 include liquefied ammonia, liquefied hydrogen, liquefied nitrogen, liquefied natural gas, liquefied ethylene gas, and liquefied petroleum gas.

[0020] As shown in Fig. 1, the pump system includes a pump 2 for pressurizing liquefied gas, a pump column 3 in which the 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, an upper lid 12 for closing the upper opening of the cover wall 10, and a head plate 20 for covering the upper opening of the purge container 1. The pump column 3 is installed in a liquefied gas storage tank 5 in which liquefied gas is stored. The pump column 3 is a hollow container extending vertically, and its upper portion protrudes 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 introduction port 8.

[0021] A suction valve 6 is provided at the bottom of the pump column 3. The 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 multiple springs 6B that urge the valve body 6A upward. When the 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 multiple springs 6B, closing the lower opening of the pump column 3. When the pump 2 is placed on the valve body 6A, the valve body 6A moves downward against the force of the springs 6B due to the weight of the pump 2, thereby opening the suction valve 6. The suction valve 6 may be an actuator-driven valve (e.g., an electric valve).

[0022] The purge vessel 1 is a device for exposing the pump 2 to a purge gas before the pump 2 is loaded into the pump column 3 and after the pump 2 is lifted out of the pump column 3. The pump system further includes a gate valve 21 disposed between the pump column 3 and the purge vessel 1. When the gate valve 21 is opened, the pump column 3 and the purge vessel 1 communicate with each other, and when the gate valve 21 is closed, the communication between the pump column 3 and the purge vessel 1 is blocked.

[0023] The purge vessel 1 has a purge gas inlet port 17 and a gas outlet port 18 which communicate with its internal space 15. The upper opening of the purge vessel 1 is covered with a head plate 20, and the lower opening of the purge vessel 1 can be closed by a gate valve 21. The gate valve 21 in this embodiment is a manual type which 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 removably fixed to the upper end of the purge container 1. The pump system includes a hanging structure 23 that suspends the pump 2 from the head plate 20. The hanging structure 23 includes a plurality of divided hanging pipes 23B connected in series. The length of each divided hanging pipe 23B is shorter than the length of the pump column 3. The hanging structure 23 is suspended from the head plate 20. Of the plurality of divided hanging pipes 23B that constitute the hanging structure 23, the uppermost divided hanging pipe 23B has a closing plate 30 that closes the through hole 50 of the head plate 20. The upper opening of the purge container 1 is closed by the head plate 20 and the closing plate 30.

[0025] The pump system includes a power cable 36 for supplying power to the pump 2. This power cable 36 extends through the multiple divided suspension pipes 23B that constitute the suspended structure 23. One end of the power cable 36 is connected to the pump 2, and the other end of the power cable 36 is connected to an electrical terminal 35 fixed to the upper surface of the top cover 12.

[0026] The pump system includes a discharge pipe 34 connected to the discharge port 2a of the pump 2. The discharge pipe 34 extends from the discharge port 2a of the pump 2 through the pump column 3 and the purge vessel 1, and is connected to the head plate 20. The pump system further includes a discharge connecting pipe 38 disposed in the cover wall 10. One end of the discharge connecting pipe 38 is connected to the discharge pipe 34, and the other end is connected to a discharge port 39 provided in the cover wall 10. The hanging structure 23, the power cable 36, and the discharge pipe 34 extend vertically through the purge vessel 1 and the pump column 3.

[0027] The discharge pipe 34 is a flexible pipe configured to be bendable. The discharge pipe 34 of this embodiment has a structure that allows it to be bent in all directions. In one embodiment, the discharge pipe 34 has a bellows structure made of a metal such as stainless steel. Unlike the hanging structure 23, the discharge pipe 34 is an integrated structure that is not divided. The discharge pipe 34 is located outside the multiple divided hanging pipes 23B that constitute the hanging structure 23, and extends vertically along the multiple divided hanging pipes 23B.

[0028] Considering the effect of piping resistance, it is preferable that the discharge pipe 34 is not a flexible pipe, but in one embodiment, taking into consideration positioning adjustment, a part of the discharge pipe 34 may be made of a flexible pipe configured to be bendable. Since a part of the discharge pipe is a flexible pipe, positioning and adjustment are easy, and by adjusting the length of the flexible pipe, it is possible to suppress the effect of the piping resistance of the flexible pipe.

[0029] FIG. 2 is an enlarged view showing one embodiment of a part of the hanging structure 23. The hanging structure 23 includes a plurality of divided hanging pipes 23B, and a plurality of screws 24 and threaded holes 25 as connectors for connecting the divided hanging pipes 23B. Each divided hanging pipe 23B has a space 26 inside through which a power cable 36 can pass. Each divided hanging pipe 23B has a hanging pipe main body 23c, and an upper flange 23d and a lower flange 23e connected to the upper end and the lower end of the hanging pipe main body 23c. The hanging pipe main body 23c has a constant outer diameter. The upper flange 23d and the lower flange 23e have a larger outer diameter than the hanging pipe main body 23c. The upper flange 23d has a threaded hole 25, and the lower flange 23e has a through hole 27 through which the screw 24 can pass.

[0030] The lower flange 23e of the upper split suspension pipe 23B and the upper flange 23d of the lower split suspension pipe 23B are in contact with each other, and the upper flange 23d and the lower flange 23e are connected by a screw 24 and a screw hole 25 as a connector. That is, the upper flange 23d and the lower flange 23e are connected by screwing the screw 24 into the screw hole 25 of the upper flange 23d through the through hole 27 of the lower flange 23e (that is, the upper split suspension pipe 23B and the lower split suspension pipe 23B are connected). In this way, the multiple split suspension pipes 23B are connected in series by the screw 24 and the screw hole 25 as a connector.

[0031] The connector is not limited to a combination of the screw 24 and the screw hole 25. For example, the connector may be a combination of a bolt and a nut, or may be a clamp, or a combination of an engagement pin and a pin stopper, or the like.

[0032] The space 26 formed inside each split suspension pipe 23B does not have to be sealed, and may be in communication with the space outside the split suspension pipe 23B. As long as the power cable 36 can pass through the space 26, the size of the space 26 is not particularly limited. In one embodiment, after the power cable 36 is placed in the space 26, the inside of the split suspension pipe 23B may be filled with a filler.

[0033] Returning to FIG. 1, the head plate 20 is covered by a cover wall 10 and a top lid 12. An electric terminal 35 is attached to the upper surface of the top lid 12. This electric terminal 35 is electrically connected to a power source (not shown). A power cable 36 connected to the electric motor of the pump 2 extends vertically inside the hanging structure 23, further extends inside the cover wall 10, and is electrically connected to the electric terminal 35.

[0034] During operation of the pump 2, the purge gas introduction port 8, the purge gas inlet port 17, and the gas outlet port 18 are each closed by a valve (not shown), and the gate valve 21 is open.

[0035] During operation of the pump 2, the liquefied gas in the liquefied gas storage tank 5 is introduced into the pump column 3 through the suction valve 6. During operation of the pump 2, the pump 2 comes into contact with the liquefied gas. In one embodiment, the pump 2 is a submersible pump configured to be able to operate in the liquefied gas. The liquefied gas pressurized by the pump 2 is transferred to the outside through the discharge pipe 34, the discharge connecting pipe 38, and the discharge port 39.

[0036] The liquefied gas pressurized by the pump 2 is discharged through a discharge pipe 34 extending through the pump column 3 and the purge container 1. Therefore, while the pump 2 is in operation, the liquid level of the liquefied gas in the pump column 3 is prevented from rising above the pump column 3. As a result, the liquefied gas is prevented from contacting components located above the pump column 3, such as the purge container 1 and the gate valve 21.

[0037] 3 is a cross-sectional view showing an embodiment of the head plate 20, the cover wall 10, and the top cover 12. The head plate 20 includes a plate body 40 having a shape that covers the upper opening of the purge container 1, a protrusion 41 extending upward from the plate body 40, a movable flange 42 surrounding the protrusion 41, and a seal 44 (e.g., a gland packing) that seals the gap between the outer surface of the protrusion 41 and the inner surface of the movable flange 42. The protrusion 41 and the movable flange 42 have a cylindrical shape. The movable flange 42 is vertically movable relative to the protrusion 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 hanging cable described later can pass.

[0038] The head plate 20 has a through hole 50 formed in the protruding portion 41. This through hole 50 extends in the vertical direction. The width of the through hole 50 is larger than the width of the hanging structure 23, and the hanging structure 23 (including the upper flange 23d and the lower flange 23e shown in FIG. 2) can pass through the through hole 50. The head plate 20 is removably fixed to the upper end of the purge vessel 1 by fasteners 53 such as bolts and nuts.

[0039] The closing plate 30 constituting the upper end of the hanging structure 23 is removably fixed to the movable flange 42 by fasteners (not shown) such as screws. The upper end of the through hole 50 is closed by the closing plate 30. The power cable 36 extends through the closing plate 30. The divided hanging pipe 23B constituting the hanging structure 23 extends through the through hole 50.

[0040] Next, an embodiment of a method for carrying the pump 2 into the pump column 3 will be described. A locking member 65 shown in Fig. 4 is used for carrying the pump 2 into the pump column 3. The locking member 65 is placed on the upper part of the head plate 20, i.e., on the protruding part 41 and / or the movable flange 42. The locking member 65 is configured to allow the suspension pipe main body 23c (see Fig. 2) of the split suspension pipe 23B to pass through, but not the upper flange 23d to pass through.

[0041] 4, the locking member 65 has an opening 66 in its center and is divided into multiple members 65A, 65A. The opening 66 is large enough not to allow the upper flange 23d of the split suspension pipe 23B to pass through. In this embodiment, the locking member 65 that functions as a stopper for the upper flange 23d is a split ring (for example, a two-split ring) made up of multiple (typically two) members.

[0042] 5 to 12 are diagrams for explaining one embodiment of a method for carrying the pump 2 into the pump column 3. The operation of carrying the pump 2 into the pump column 3 includes an operation of drying up the pump 2 by exposing it to purge gas in the purge container 1, an operation of adding (connecting) the multiple divided suspension pipes 23B one by one to the hanging structure 23, and an operation of lowering the pump 2 in the pump column 3.

[0043] In step 101, liquefied gas is discharged from the pump column 3. Specifically, the gate valve 21 is closed, and purge gas is supplied into the pump column 3 from the purge gas inlet port 8, and the liquefied gas is discharged from the pump column 3 through the suction valve 6 by the pressure of the purge gas. At this time, since the gate valve 21 is closed, the liquefied gas can be discharged from the pump column 3 without discharging the liquefied gas and gas evaporated from the liquefied gas to the outside through the purge container 1. Prior to this step 101, the head plate 20 and the discharge connecting pipe 38 are removed. The upper opening of the purge container 1 is closed by the cover wall 10 and the top lid 12. In step 102 , the cover wall 10 , the top lid 12 , and the electrical terminals 35 are removed from the purge vessel 1 .

[0044] In step 103, the lifting cable 62 of the lifting device 61 is connected to the cable port 47 of the head plate 20. Examples of the lifting device 61 include a hoist and a winch. The locking member 65 described with reference to FIG. 4 is placed on the head plate 20. One divided suspension pipe 23B of the suspension structure 23 extends through the through hole 50 of the head plate 20. The lower flange 23e of this divided suspension pipe 23B is connected to the pump 2, and the upper flange 23d of the divided suspension pipe 23B is supported by the locking member 65 on the head plate 20. The divided suspension pipe 23B and the pump 2 are suspended from the head plate 20. The power cable 36 extends upward through the divided suspension pipe 23B connected to the pump 2. The discharge pipe 34 extends upward from the pump 2 through the head plate 20.

[0045] The width of the locking member 65 is larger than the width of the through hole 50 of the head plate 20, and the locking member 65 cannot pass through this through hole 50. On the other hand, the width of the upper flange 23d and the lower flange 23e of the split suspension pipe 23B is smaller than the width of the through hole 50 of the head plate 20, and the split suspension pipe 23B can pass through the through hole 50. However, as long as the upper flange 23d is supported by the locking member 65, the split suspension pipe 23B cannot pass through the through hole 50. Therefore, the pump 2 is suspended from the locking member 65 on the head plate 20 by the split suspension pipe 23B. The load of the pump 2 is supported by the head plate 20 via the split suspension pipe 23B and the locking member 65.

[0046] In step 104, the lifting device 61 lowers the divided suspension pipe 23B, the pump 2, the head plate 20, the locking member 65, the power cable 36, and the discharge pipe 34 together, so that the top opening of the purge vessel 1 is covered by the head plate 20. The head plate 20 is fixed to the upper end of the purge vessel 1 by the fasteners 53 shown in FIG.

[0047] In step 105, the suspension cable 62 of the lifting device 61 is disconnected from the cable port 47. One of the multiple split suspension pipes 23B prepared in advance is added to the suspended structure 23. More specifically, the upper flange 23d of the newly added split suspension pipe 23B is connected to the suspension cable 62 of the lifting device 61, and the lower flange 23e of the newly added split suspension pipe 23B is connected to the upper flange 23d of the split suspension pipe 23B suspended from the locking member 65. The connection between the split suspension pipes 23B is achieved by the screw 24 and the screw hole 25 as the connector described with reference to FIG. 2. When adding a split suspension pipe 23B, the power cable 36 is passed through the split suspension pipe 23B to be added.

[0048] In step 106, with the upper opening of the purge vessel 1 covered with the head plate 20 and the lower opening of the purge vessel 1 closed with the gate valve 21, the internal space 15 of the purge vessel 1 housing the pump 2 is evacuated through the gas outlet port 18. Then, a purge gas (e.g., an inert gas and / or a gas having the same components as the liquefied gas) is supplied from the purge gas inlet port 17 to the internal space 15, filling the internal space 15 with the purge gas. The pump 2 is exposed to (comes into contact with) the purge gas in the purge vessel 1, thereby removing air and moisture from the surface of the pump 2. This process is a drying-up process that drives away air and moisture from the pump 2. The evacuation of the internal space 15 and the supply of the purge gas to the internal space 15 may be repeated.

[0049] The purge gas used is a gas composed of components having a boiling point lower than the boiling point of the liquefied gas to be pumped by the 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, when the liquefied gas to be pumped by the pump 2 is liquefied natural gas, nitrogen gas, which is a gas composed of nitrogen having 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, when the liquefied gas to be pumped by the pump 2 is liquid hydrogen, helium gas, which is a gas composed of helium having a boiling point (-269°C) lower than the boiling point of hydrogen (-253°C), is used as the purge gas.

[0050] A portion of the purge gas may be a gas having the same composition as the liquefied gas. When the gas outlet port 18 is connected to a gas processing device, all of the purge gas may be a gas having the same composition as the liquefied gas. For example, when the liquefied gas is liquefied hydrogen, some or all of the purge gas may be hydrogen gas. In another example, when the liquefied gas is liquefied ammonia, some or all of the purge gas may be ammonia gas.

[0051] In step 107, the lifting device 61 slightly lifts the hanging structure 23 and the pump 2, and the locking member 65 is removed from the head plate 20. The load of the pump 2 is supported by the lifting device 61. The supply of purge gas into the purge vessel 1 through the purge gas inlet port 17 is continued to prevent air from entering through the through hole 50 of the head plate 20. Meanwhile, the evacuation of the internal space 15 of the purge vessel 1 through the gas outlet port 18 is stopped. Furthermore, the gate valve 21 is opened. The purge gas supplied into the purge vessel 1 is discharged to the outside of the purge vessel 1 through the through hole 50 of the head plate 20. This outward flow of the purge gas prevents the surrounding air from entering the purge vessel 1.

[0052] In step 108, the lifting device 61 further lowers the suspended structure 23, the pump 2, the power cable 36, and the discharge pipe 34. While the pump 2 is being lowered, purge gas may be supplied from the purge gas introduction port 8 into the pump column 3. Before the upper flange 23d of the uppermost divided suspension pipe 23B enters the purge container 1, the locking member 65 is placed on the head plate 20 again. The power cable 36 is connected to a power cable payout device (not shown), and the power cable 36 is paid out as the pump 2 is lowered. The discharge pipe 34 is similarly paid out as the pump 2 is lowered. The power cable 36 and the discharge pipe 34 are lowered as the pump 2 and the suspended structure 23 are lowered. When the pump 2 is lowered, the divided suspension pipe 23B and the power cable 36 extend through the through hole 50 of the head plate 20.

[0053] In step 109, the hanging structure 23, the pump 2, the power cable 36, and the discharge pipe 34 are lowered by the lifting device 61 until the upper flange 23d of the uppermost divided suspension pipe 23B engages with (comes into contact with) the locking member 65. When the upper flange 23d of the uppermost divided suspension pipe 23B engages with the locking member 65, the load of the pump 2 is supported by the locking member 65 and the head plate 20.

[0054] Then, the process of adding (connecting) the remaining multiple divided suspension pipes 23B one by one to the hanging structure 23 is repeated in the same manner as in step 105 and steps 107 to 109 described above, until the pump 2 approaches the bottom of the pump column 3. While the 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. During the operation of adding (connecting) the multiple divided suspension pipes 23B one by one, the purge gas enters the interior of each divided suspension pipe 23B and expels air from the interior of each divided suspension pipe 23B.

[0055] In step 110, when the pump 2 approaches the bottom of the pump column 3, the last divided suspension pipe 23B is added (connected) to the suspension structure 23. This last divided suspension pipe 23B has a closing plate 30 at its upper end. In step 111, the locking member 65 is removed from the head plate 20, and then the hanging structure 23 and the pump 2 are lowered by the lifting device 61 until the closure plate 30 reaches a position directly above the head plate 20. The pump 2 is placed in a predetermined position directly above the suction valve 6 in the pump column 3. In step 112, the movable flange 42 of the head plate 20 is raised upward and the movable flange 42 is secured to the closure plate 30 with fasteners (not shown), such as screws.

[0056] In step 113, the closure plate 30, the movable flange 42, the hanging structure 23, and the pump 2 are lowered by the lifting device 61 until the closure plate 30 contacts the head plate 20. The pump 2 is placed on the suction valve 6. The suction valve 6 opens due to the weight of the pump 2. In step 114, the suspending cable 62 of the lifting device 61 is disconnected from the closing plate 30, and the supply of the purge gas to the purge vessel 1 is stopped. The liquefied gas in the liquefied gas storage tank 5 flows into the pump column 3 through the suction valve 6.

[0057] In step 115 , the cover wall 10 is secured to the upper end of the purge vessel 1 . In step 116, the discharge connecting pipe 38 is connected to the discharge pipe 34 and the discharge port 39, and the top cover 12 is moved above the cover wall 10. The power cable 36 is connected to an electric terminal 35 installed on the upper surface of the top cover 12, and the top cover 12 is fixed to the cover wall 10. The upper opening of the cover wall 10 is closed by the top cover 12.

[0058] According to this embodiment, the pump 2 can be loaded into the pump column 3 with the top opening of the purge container 1 covered by the head plate 20. Therefore, the amount of purge gas used to prevent the boil-off gas (BOG) generated by vaporization of the liquefied gas from being released into the atmosphere and / or to prevent air from flowing into the pump column 3 can be reduced.

[0059] Next, one embodiment of a method for lifting the pump 2 from the pump column 3 will be described with reference to Figures 13 to 17. In lifting the pump 2, the steps described with reference to Figures 5 to 12 are basically performed in reverse order. The series of operations shown in Figures 13 to 17 includes an operation of lifting the pump 2 in the pump column 3, an operation of removing the multiple divided suspension pipes 23B one by one from the hanging structure 23, and a hot-up operation of exposing the pump 2 to purge gas in the purge container 1.

[0060] In step 201, the top cover 12 is removed from the cover wall 10, and the power cable 36 is disconnected from the electrical terminal 35. The discharge manifold 38 is disconnected from the discharge pipe 34 and is then removed from the cover wall 10. The cover wall 10 is then removed from the purge vessel 1. In step 202, the lifting cable 62 of the lifting device 61 is connected to the closure plate 30 of the uppermost split suspension pipe 23B, thereby connecting the lifting device 61 to the suspension structure 23 connected to the pump 2 via the closure plate 30.

[0061] In step 203, the lifting device 61 slightly lifts the closing plate 30, the movable flange 42, the hanging structure 23, and the 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 in 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. At this time, since the through hole 50 of the head plate 20 is closed by the closing plate 30, the liquefied gas can be discharged from the pump column 3 without discharging the liquefied gas and the gas evaporated from the liquefied gas to the outside through the purge container 1.

[0062] In step 204, the movable flange 42 is separated from the closing plate 30. Furthermore, the hanging structure 23 and the pump 2 are raised by the lifting device 61 until the entire uppermost divided suspension pipe 23B is positioned above the purge container 1. Thereafter, the locking member 65 is placed on the head plate 20. When the pump 2 is raised, the discharge pipe 34 and the power cable 36 are also raised. When the pump 2 is raised, the divided suspension pipe 23B and the power cable 36 extend through the through hole 50 of the head plate 20. The purge gas supplied into the purge container 1 is discharged to the outside of the purge container 1 through the through hole 50 of the head plate 20. This outward flow of the purge gas prevents the ambient air from entering the purge container 1.

[0063] In step 205, the hanging structure 23 and the pump 2 are slightly lowered by the lifting device 61 until the upper flange 23d directly above the locking member 65 engages (contacts) with the locking member 65. The load of the pump 2 is supported by the locking member 65 and the head plate 20. In step 206, the uppermost divided suspension pipe 23B outside the purge container 1 is removed from the hanging structure 23. At this time, the power cable 36 is pulled out from the divided suspension pipe 23B that has been removed. In step 207, the lifting cable 62 of the lifting device 61 is connected to the upper flange 23d of the split suspension pipe 23B supported by the locking member 65. Thereby, the lifting device 61 is connected to the suspended structure 23 and the pump 2 again.

[0064] Then, the multiple divided suspension pipes 23B are repeatedly removed (disconnected) one by one from the hanging structure 23 in the same manner as in steps 204 to 207 above until the pump 2 is pulled up into the purge container 1 by the lifting device 61. While the pump 2 is being pulled up, purge gas is supplied into the pump column 3 from the purge gas inlet port 17 and / or the purge gas introduction port 8.

[0065] In step 208, the pump 2 is closed by the gate valve 21 while it is located in the purge container 1. 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 housing the pump 2 is evacuated through the gas outlet port 18. Thereafter, a purge gas (e.g., an inert gas and / or a gas having the same components as the liquefied gas) is supplied from the purge gas inlet port 17 to the internal space 15, filling the internal space 15 with the purge gas. The pump 2 is exposed to (comes into contact with) the purge gas in the purge container 1, thereby heating the pump 2. This process is a hot-up process for heating the pump 2. The evacuation of the internal space 15 and the supply of the purge gas to the internal space 15 may be repeated.

[0066] In step 209, fasteners 53 (see FIG. 2), such as bolts and nuts, that secure the head plate 20 to the purge container 1 are removed. After that, the hanging cable 62 is connected to the cable port 47 of the head plate 20. Then, the head plate 20, the power cable 36, the locking member 65, the pump 2, and the discharge pipe 34 are raised together by the lifting device 61, and the pump 2 is moved outside the purge container 1.

[0067] According to this embodiment, the pump 2 can be pulled up from the pump column 3 with the top opening of the purge container 1 covered by the head plate 20. Therefore, the amount of purge gas used to prevent the boil-off gas (BOG) generated by vaporization of the liquefied gas remaining in the pump column 3 from being released into the atmosphere and / or to prevent air from flowing into the pump column 3 can be reduced.

[0068] Next, another embodiment of the pump system will be described. Fig. 18 is a diagram for explaining another embodiment of the pump system. The configuration and operation of this embodiment that are not specifically described are the same as those of the embodiment described with reference to Figs. 1 to 17, so that the overlapping description will be omitted.

[0069] As shown in Fig. 18, in this embodiment, the discharge pipe 34 and the power cable 36 are disposed inside the hanging structure 23. That is, the discharge pipe 34 and the power cable 36 extend through a plurality of divided hanging pipes 23B connected in series. The pump system includes a branch pipe 69 disposed inside the cover wall 10. This branch pipe 69 is connected to the closing plate 30 of the uppermost divided hanging pipe 23B.

[0070] The discharge pipe 34 and the power cable 36 are branched in two directions in the branch pipe 69. That is, the discharge pipe 34 is connected to a discharge connecting pipe 38 connected to the outer surface of the branch pipe 69, and the power cable 36 is connected to an electric terminal 35 fixed to the outer surface of the cover wall 10. In the embodiment shown in FIG. 18, the discharge pipe 34 extends to the upper part of the branch pipe 69, and the power cable 36 extends to the side part of the branch pipe 69, but the configuration of the branch pipe 69 and the arrangement of the discharge pipe 34 and the power cable 36 are not limited to this embodiment.

[0071] The liquefied gas pressurized by the pump 2 is discharged through the discharge pipe 34 extending through the hanging structure 23, the pump column 3, and the purge vessel 1. Therefore, while the pump 2 is in operation, the liquid level of the liquefied gas in the pump column 3 is prevented from rising above the pump column 3. As a result, the liquefied gas is prevented from contacting components located above the pump column 3, such as the purge vessel 1 and the gate valve 21.

[0072] The pump system includes a flow path switching device 70 disposed in the hanging structure 23. The flow path switching device 70 is located in the lowermost divided hanging pipe 23B, and is connected to the discharge port of the pump 2 and the discharge pipe 34.

[0073] FIG. 19 is a cross-sectional view showing an embodiment of a detailed configuration of the flow path switching device 70. As shown in FIG. 19, the flow path switching device 70 includes a flow path structure 75 having a first flow path 71, a second flow path 72, and a third flow path 73, and a valve body 77 arranged in the flow path structure 75. The first flow path 71 communicates with the discharge port 2b of the pump 2, the second flow path 72 communicates with the inside of the divided suspension pipe 23B, and the third flow path 73 communicates with the discharge pipe 34. The valve body 77 is arranged to selectively communicate the third flow path 73 with either the first flow path 71 or the second flow path 72. The configuration of the flow path switching device 70 is not limited to the embodiment shown in FIG. 19 as long as it can perform its intended function.

[0074] 19 shows the state of the flow path switching device 70 when the pump 2 is not operating. The valve body 77 is pressed against the flow path structure 75 by the spring 80 to close the first flow path 71. More specifically, the flow path structure 75 has a valve seat 81 formed around the outlet of the first flow path 71, and the valve body 77 is pressed against the valve seat 81 by the spring 80. Therefore, while the valve body 77 is pressed against the valve seat 81, the first flow path 71 is closed, and the second flow path 72 and the third flow path 73 are in communication. The second flow path 72 is open inside the divided hanging pipe 23B.

[0075] The flow path switching device 70 is provided to expel air from the hanging structure 23 including the multiple divided hanging pipes 23B shown in FIG. 18 by using a purge gas. That is, the discharge pipe 34 is connected to a purge gas supply source (not shown), and the purge gas is supplied from the purge gas supply source into the discharge pipe 34. As shown in FIG. 19, the purge gas flows through the discharge pipe 34 toward the pump 2 and flows into the flow path structure 75 through the third flow path 73. Since the second flow path 72 and the third flow path 73 are connected to each other, the purge gas flows out of the flow path structure 75 through the second flow path 72 and flows into the divided hanging pipe 23B. The purge gas is discharged through the divided hanging pipe 23B. This flow of the purge gas can remove air from the inside of the hanging structure 23 and the discharge pipe 34.

[0076] 20 shows the state of the flow path switching device 70 when the pump 2 is operating. When the pump 2 is operating, the liquefied gas is discharged from the discharge port 2b of the pump 2 and flows into the first flow path 71 of the flow path switching device 70. The liquefied gas flowing through the first flow path 71 moves the valve body 77 against the force of the spring 80, opening the first flow path 71 and closing the second flow path 72 with the valve body 77. As a result, the first flow path 71 and the third flow path 73 are connected, and the liquefied gas flows into the discharge pipe 34.

[0077] When the operation of the pump 2 stops, the valve body 77 is pressed against the valve seat 81 by the spring 80. As a result, as shown in Fig. 19, the first flow path 71 is closed and the second flow path 72 and the third flow path 73 are connected. In this manner, the flow path switching device 70 of the present embodiment is operated only by the spring 80 and the flow of the liquefied gas. In one embodiment, the flow path switching device 70 may have an actuator (e.g., an electric actuator or a fluid actuator) that moves the valve body 77.

[0078] Figures 21 to 28 are diagrams for explaining one embodiment of a method for carrying the pump 2 into the pump column 3 in the pump system shown in Figure 18. Details of this embodiment that are not particularly explained are the same as those of the embodiment explained with reference to Figures 5 to 12, so duplicate explanations will be omitted.

[0079] In step 301, liquefied gas is discharged from the pump column 3. Specifically, the gate valve 21 is closed, and purge gas is supplied into the pump column 3 from the purge gas inlet port 8, and the liquefied gas is discharged from the pump column 3 through the suction valve 6 by the pressure of the purge gas. At this time, since the gate valve 21 is closed, the liquefied gas can be discharged from the pump column 3 without discharging the liquefied gas and the gas evaporated from the liquefied gas to the outside through the purge container 1. Prior to this step 301, the head plate 20, the branch pipe 69, and the discharge connecting pipe 38 are removed. The upper opening of the purge container 1 is closed by the cover wall 10 and the top lid 12. In step 302 , the cover wall 10 , the top lid 12 , and the electrical terminals 35 are removed from the purge vessel 1 .

[0080] In step 303, the hanging cable 62 of the lifting device 61 is connected to the cable port 47 of the head plate 20. The locking member 65 described with reference to FIG. 4 is placed on the head plate 20. One divided hanging pipe 23B of the hanging structure 23 extends through the through hole 50 of the head plate 20. The lower flange 23e of this divided hanging pipe 23B is connected to the pump 2, and the upper flange 23d of the divided hanging pipe 23B is supported by the locking member 65 on the head plate 20. The divided hanging pipe 23B and the pump 2 are suspended from the head plate 20. The discharge pipe 34 and the power cable 36 extend upward through the divided hanging pipe 23B connected to the pump 2. The load of the pump 2 is supported by the head plate 20 via the divided hanging pipe 23B and the locking member 65.

[0081] In step 304, the lifting device 61 lowers the divided suspension pipe 23B, the pump 2, the head plate 20, the locking member 65, the power cable 36, and the discharge pipe 34 together, so that the top opening of the purge vessel 1 is covered by the head plate 20. The head plate 20 is fixed to the upper end of the purge vessel 1 by the fasteners 53 shown in FIG.

[0082] In step 305, the suspension cable 62 of the lifting device 61 is disconnected from the cable port 47. One of the multiple split suspension pipes 23B prepared in advance is added to the suspended structure 23. More specifically, the upper flange 23d of the newly added split suspension pipe 23B is connected to the suspension cable 62 of the lifting device 61, and the lower flange 23e of the newly added split suspension pipe 23B is connected to the upper flange 23d of the split suspension pipe 23B suspended from the locking member 65. The connection between the split suspension pipes 23B is achieved by the screw 24 and the screw hole 25 as the connector described with reference to FIG. 2. When adding the split suspension pipe 23B, the discharge pipe 34 and the power cable 36 are passed through the split suspension pipe 23B to be added.

[0083] In step 306, with the upper opening of the purge vessel 1 covered by the head plate 20 and the lower opening of the purge vessel 1 closed by the gate valve 21, the internal space 15 of the purge vessel 1 housing the pump 2 is evacuated through the gas outlet port 18. Then, a purge gas (e.g., an inert gas and / or a gas having the same components as the liquefied gas) is supplied from the purge gas inlet port 17 to the internal space 15, filling the internal space 15 with the purge gas. The pump 2 is exposed to (comes into contact with) the purge gas in the purge vessel 1, thereby removing air and moisture from the surface of the pump 2. This process is a drying-up process that drives away air and moisture from the pump 2. The evacuation of the internal space 15 and the supply of the purge gas to the internal space 15 may be repeated.

[0084] Simultaneously with the drying-up operation, or before or after the drying-up operation, purge gas is supplied into the discharge pipe 34 to expel air from the inside of the discharge pipe 34 and the split hanging pipe 23B. The discharge pipe 34 is connected to a purge gas supply source (not shown). The purge gas flows downward in the discharge pipe 34, turns back in the flow path switching device 70 described with reference to FIG. 19, flows into the split hanging pipe 23B, and is discharged through the split hanging pipe 23B. Air is removed from the inside of the discharge pipe 34 and the split hanging pipe 23B by this flow of purge gas.

[0085] In step 307, the lifting device 61 slightly lifts the hanging structure 23 and the pump 2, and the locking member 65 is removed from the head plate 20. The load of the pump 2 is supported by the lifting device 61. The supply of purge gas into the purge vessel 1 through the purge gas inlet port 17 is continued to prevent air from entering through the through hole 50 of the head plate 20. Meanwhile, the evacuation of the internal space 15 of the purge vessel 1 through the gas outlet port 18 is stopped. Furthermore, the gate valve 21 is opened. The purge gas supplied into the purge vessel 1 is discharged to the outside of the purge vessel 1 through the through hole 50 of the head plate 20. This outward flow of the purge gas prevents the ambient air from entering the purge vessel 1.

[0086] In step 308, the lifting device 61 further lowers the suspended structure 23, the pump 2, the power cable 36, and the discharge pipe 34. While the pump 2 is being lowered, purge gas may be supplied from the purge gas introduction port 8 into the pump column 3. Before the upper flange 23d of the uppermost divided suspension pipe 23B enters the purge container 1, the locking member 65 is placed on the head plate 20 again. The power cable 36 is connected to a power cable payout device (not shown), and the power cable 36 is paid out as the pump 2 is lowered. The discharge pipe 34 is similarly paid out as the pump 2 is lowered. The power cable 36 and the discharge pipe 34 are lowered as the pump 2 and the suspended structure 23 are lowered. When the pump 2 is lowered, the divided suspension pipe 23B, the discharge pipe 34, and the power cable 36 extend through the through hole 50 of the head plate 20.

[0087] In step 309, the hanging structure 23, the pump 2, the power cable 36, and the discharge pipe 34 are lowered by the lifting device 61 until the upper flange 23d of the uppermost divided suspension pipe 23B engages with (comes into contact with) the locking member 65. When the upper flange 23d of the uppermost divided suspension pipe 23B engages with the locking member 65, the load of the pump 2 is supported by the locking member 65 and the head plate 20.

[0088] Then, the process of adding (connecting) the remaining multiple split suspension pipes 23B one by one to the hanging structure 23 is repeated in the same manner as in the above step 305 and steps 307 to 309, until the pump 2 approaches the bottom of the pump column 3. While the 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. Every time a split suspension pipe 23B is added (connected), the process of removing air from the discharge pipe 34 and the inside of the split suspension pipe 23B by the purge gas, described in the above step 306, is repeated.

[0089] In step 310, when the pump 2 approaches the bottom of the pump column 3, the last divided suspension pipe 23B is added (connected) to the suspension structure 23. This last divided suspension pipe 23B has a closing plate 30 at its upper end. In step 311, the locking member 65 is removed from the head plate 20, after which the hanging structure 23 and the pump 2 are lowered by the lifting device 61 until the closure plate 30 reaches a position directly above the head plate 20. The pump 2 is placed in a predetermined position directly above the suction valve 6 in the pump column 3. In step 312, the movable flange 42 of the head plate 20 is raised upward and the movable flange 42 is secured to the closure plate 30 with fasteners (not shown), such as screws.

[0090] In step 313, the closure plate 30, the movable flange 42, the hanging structure 23, and the pump 2 are lowered by the lifting device 61 until the closure plate 30 contacts the head plate 20. The pump 2 is placed on the suction valve 6. The suction valve 6 opens due to the weight of the pump 2. In step 314, the suspending cable 62 of the lifting device 61 is disconnected from the closing plate 30, and the supply of the purge gas to the purge vessel 1 is stopped. The liquefied gas in the liquefied gas storage tank 5 flows into the pump column 3 through the suction valve 6.

[0091] In step 315 , the cover wall 10 is secured to the upper end of the purge vessel 1 . In step 316, the branch pipe 69 and the discharge connecting pipe 38 are placed in the cover wall 10. The branch pipe 69 is connected to the closing plate 30. The discharge pipe 34 and the power cable 36 are branched into two directions in the branch pipe 69. The power cable 36 is connected to the electrical terminal 35, and the discharge pipe 34 is connected to the discharge connecting pipe 38. Furthermore, the discharge connecting pipe 38 is connected to the discharge port 39 of the cover wall 10. The top cover 12 is attached to the cover wall 10, and the upper opening of the cover wall 10 is closed by the top cover 12 (see FIG. 18 ).

[0092] Next, one embodiment of a method for lifting the pump 2 from the pump column 3 in the pump system shown in Fig. 18 will be described with reference to Figs. 29 to 33. In lifting the pump 2, the steps described with reference to Figs. 21 to 28 are basically performed in reverse order. The series of operations shown in Figs. 29 to 33 includes an operation of lifting the pump 2 in the pump column 3, an operation of removing the multiple divided suspension pipes 23B one by one from the hanging structure 23, and a hot-up operation of exposing the pump 2 to purge gas in the purge container 1.

[0093] In step 401, the top cover 12 is removed from the cover wall 10, and the power cable 36 is disconnected from the electrical terminal 35. The discharge manifold 38 is disconnected from the discharge pipe 34, and the discharge manifold 38 and the branch pipe 69 are removed from the cover wall 10. In step 402 , the cover wall 10 is removed from the purge vessel 1 . In step 403, the lifting cable 62 of the lifting device 61 is connected to the closure plate 30 of the uppermost split suspension pipe 23B, thereby connecting the lifting device 61 to the suspension structure 23 connected to the pump 2 via the closure plate 30.

[0094] In step 404, the lifting device 61 slightly lifts the closing plate 30, the movable flange 42, the hanging structure 23, and the 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 in 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. At this time, since the through hole 50 of the head plate 20 is closed by the closing plate 30, the liquefied gas can be discharged from the pump column 3 without discharging the liquefied gas and the gas evaporated from the liquefied gas to the outside through the purge container 1.

[0095] In step 405, the movable flange 42 is separated from the closing plate 30. Furthermore, the hanging structure 23 and the pump 2 are raised by the lifting device 61 until the entire uppermost divided suspension pipe 23B is positioned above the purge container 1. Thereafter, the locking member 65 is placed on the head plate 20. When the pump 2 is raised, the discharge pipe 34 and the power cable 36 are also raised. When the pump 2 is raised, the divided suspension pipe 23B, the discharge pipe 34, and the power cable 36 extend through the through hole 50 of the head plate 20. The purge gas supplied into the purge container 1 is discharged to the outside of the purge container 1 through the through hole 50 of the head plate 20. This outward flow of the purge gas prevents the surrounding air from entering the purge container 1.

[0096] In step 406, the hanging structure 23 and the pump 2 are slightly lowered by the lifting device 61 until the upper flange 23d directly above the locking member 65 engages (contacts) with the locking member 65. The load of the pump 2 is supported by the locking member 65 and the head plate 20. In step 407, the uppermost divided suspension pipe 23B outside the purge vessel 1 is removed from the hanging structure 23. At this time, the discharge pipe 34 and the power cable 36 are pulled out from the removed divided suspension pipe 23B.

[0097] In step 408, the lifting cable 62 of the lifting device 61 is connected to the upper flange 23d of the split suspension pipe 23B supported by the locking member 65. Thereby, the lifting device 61 is connected to the suspended structure 23 and the pump 2 again. Then, the multiple divided suspension pipes 23B are repeatedly removed (disconnected) one by one from the hanging structure 23 in the same manner as in steps 405 to 408 above until the pump 2 is pulled up into the purge container 1 by the lifting device 61. While the pump 2 is being pulled up, purge gas is supplied into the pump column 3 from the purge gas inlet port 17 and / or the purge gas introduction port 8.

[0098] In step 409, the pump 2 is closed by the gate valve 21 while it is located in the purge container 1. 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 containing the pump 2 is evacuated through the gas outlet port 18. Thereafter, a purge gas (e.g., an inert gas and / or a gas having the same components as the liquefied gas) is supplied from the purge gas inlet port 17 to the internal space 15, filling the internal space 15 with the purge gas. The pump 2 is exposed to (comes into contact with) the purge gas in the purge container 1, thereby heating the pump 2. This process is a hot-up process for heating the pump 2. The evacuation of the internal space 15 and the supply of the purge gas to the internal space 15 may be repeated.

[0099] In step 410, fasteners 53 (see FIG. 2), such as bolts and nuts, that secure the head plate 20 to the purge container 1 are removed. After that, the hanging cable 62 is connected to the cable port 47 of the head plate 20. Then, the head plate 20, the power cable 36, the locking member 65, the pump 2, and the discharge pipe 34 are raised together by the lifting device 61, and the pump 2 is moved outside the purge container 1.

[0100] The above-described embodiments have been described for the purpose of enabling a person having ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments are naturally possible for a person skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope according to the technical idea defined by the claims. [Explanation of symbols]

[0101] 1 Purge vessel 2. Pump 3. Pump column 5 Liquefied gas storage tank 6. Suction valve 8 Purge gas inlet port 10 Covering walls 12 Top lid 15. Interior Space 17 Purge gas inlet port 18 Gas outlet port 20 Head Plate 21 Gate valve 23 Suspended Structure 23B Split suspension pipe 23c Hanging pipe body 23d Upper flange 23e Lower flange 24 Screws 25 screw holes 26 Space 27 Through hole 30 Closing plate 35 Electrical terminals 34 Discharge pipe 36 Power Cable 38 Discharge connection pipe 39 Discharge port 40 Plate body 41 Protrusion 42 Movable flange 44 Seal 47 Cable Port 50 through holes 53 Fasteners 61 Lifting device 62 Suspension Cable 65 Locking member 66 Aperture 69 Branch Pipe 70 Flow path switching device 71 First Channel 72 Second Stream 73 3rd Stream 75 Flow path structure 77 Valve body 80 Spring 81 Valve seat

Claims

1. A pump for pressurizing the liquefied gas; a pump column in which the pump is disposed; a purge vessel coupled to the pump column; a power cable extending through the pump column and the purge receptacle and coupled to the pump; a suspension structure including a plurality of divided suspension tubes extending through the pump column and the purge vessel and connected to the pump; a discharge pipe extending through the pump column and the purge container and connected to a discharge port of the pump; The plurality of divided suspension pipes are connected in a row and configured to be detachable from one another, A pump system, wherein at least a portion of the discharge pipe is made of a flexible pipe configured to be able to bend.

2. The pump system of claim 1 , wherein the discharge pipe is disposed outside the hanging structure.

3. The pump system of claim 1 , wherein the discharge pipe is disposed within the hanging structure.

4. a flow path switching device disposed within the hanging structure and connected to the discharge port of the pump and the discharge pipe; 4. The pump system of claim 3, wherein the flow path switching device comprises a flow path structure having a first flow path, a second flow path, and a third flow path, and a valve body disposed within the flow path structure and selectively connecting the third flow path to either the first flow path or the second flow path, the first flow path communicating with a discharge port of the pump, the second flow path communicating with an interior of the hanging structure, and the third flow path communicating with the discharge pipe.

5. The pump system of claim 1 , wherein the power cable is disposed within the hanging structure.

6. The pump system of claim 1 , further comprising a gate valve disposed between the pump column and the purge reservoir.

7. The purge container further includes a head plate having a shape that covers an upper opening of the purge container, The pump system according to claim 1 , wherein an uppermost split suspension pipe among the plurality of split suspension pipes is connected to the head plate.

8. 1. A method for installing a pump used to transport liquefied gas into a pump column, comprising the steps of: A suspension structure connected to a lifting device is connected to the pump, and the suspension structure includes at least one of a plurality of divided suspension pipes prepared in advance; The remaining parts of the plurality of divided suspension pipes are connected to the suspension structure one by one, while the lifting device lowers the pump and the suspension structure within the pump column and the purge container, the purge container being connected to the pump column; The method includes lowering the pump and the hanging structure within the pump column and the purge receptacle while lowering a discharge pipe and a power cable connected to the pump within the pump column and the purge receptacle, at least a portion of the discharge pipe being comprised of a flexible pipe configured to bend.

9. The method of claim 8 , wherein the discharge pipe is located outside the hanging structure.

10. The method of claim 8 , wherein the discharge pipe is disposed within the hanging structure.

11. The method of claim 8 , wherein the power cable is disposed within the hanging structure.

12. The method of claim 8 further comprising providing a purge gas within the discharge line and the hanging structure.

13. 1. A method of lifting a pump used to transport liquefied gas from a pump column, comprising the steps of: A lifting device is used to raise the pump and the hanging structure within the pump column and the purge container while disconnecting a plurality of divided hanging pipes one by one from a hanging structure connected to the pump, the hanging structure including the plurality of divided hanging pipes connected in series, and the purge container is connected to the pump column; The method includes raising the pump and the hanging structure within the pump column and the purge receptacle while raising a discharge pipe and a power cable connected to the pump within the pump column and the purge receptacle, at least a portion of the discharge pipe being comprised of a flexible pipe configured to bend.

14. The method of claim 13 , wherein the discharge pipe is located outside the hanging structure.

15. The method of claim 13 , wherein the discharge pipe is disposed within the hanging structure.

16. The method of claim 13 , wherein the power cable is disposed within the hanging structure.

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