Pump installation device, pump installation method, and pump withdrawal method

Abstract

To provide a pump installation device which can reduce a quantity of a purge gas for use in the prevention of the discharge of a boil-off gas (BOG) from a pump column at the carry-in of a submerged-type pump to the pump column and the pullup of the pump from the pump column, and can construct a safety working environment.SOLUTION: A pump installation device comprises: a working chamber 1 which forms a closed working space 15; an actuator drive-type door 12 for covering an upper opening 3a of a pump column 3; a suspension cable 23 for suspending a submerged-type pump 2 into the pump column 3; and a crane 40 for ascending and descending the suspension cable 23. The upper opening 3a of the pump column 3, the actuator drive-type door 12 and the crane 40 are arranged in the working space 15.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pump installation device for installing a submersible pump for boosting liquefied gas such as liquefied ammonia, liquefied natural gas (LNG), or liquid hydrogen in a pump column and removing the pump from the pump column. Further, the present invention relates to a method for installing a submersible pump in a pump column and a method for removing a submersible pump from a pump column using such a pump installation device.

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. Applications of hydrogen as an energy source include fuel cells and turbine power generation. Since natural gas, ammonia, and hydrogen are in a gaseous state at normal temperature, they are cooled and liquefied for storage and transportation. Liquefied 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 or a factory 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. The pump 500 is installed in a vertical pump column 505 installed in the 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.

[0004] When pump 500 is operated, the liquefied gas in the liquefied gas storage tank 501 is drawn into the pump column 505, rises up the pump column 505, and is then discharged from the pump column 505 through the liquefied gas discharge port 509. The pump column 505 is provided with a purge gas introduction port 512. This purge gas introduction port 512 is closed when pump 500 is in operation.

[0005] Figure 20 illustrates the process of moving the pump 500 into the pump column 505 and the process of lifting the pump 500 out of the pump column 505. When installing the pump 500 inside the pump column 505, and when lifting the pump 500 out of the pump column 505 for maintenance or other purposes, the top cover 510 is removed and the cable 508 is connected to the hoisting machine 513. The pump 500 is suspended by the cable 508 and raised or lowered inside the pump column 505 by the hoisting machine 513.

[0006] The liquefied gas remaining in the pump column 505 vaporizes to form boil-off gas (BOG). During the loading and unloading of the pump 500, purge gas is introduced into the pump column 505 through the purge gas introduction port 512 to prevent this boil-off gas (BOG) from being released into the atmosphere. The purge gas also serves to prevent air from entering the pump column 505. Inert gases such as N2 gas and He gas are used as the purge gas. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 3197645 [Patent Document 2] Patent No. 3198248 [Patent Document 3] Patent No. 3472379 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, because 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 boil-off gas (BOG) from being released outside the pump column 505 while preventing air from entering the pump column 505. In particular, helium gas is expensive, which increases the cost of transporting and retrieving the pump 500.

[0009] Furthermore, during the loading and unloading of pump 500, workers may be exposed to boil-off gas, potentially compromising a safe working environment. In particular, when lifting cable 508 from pump column 505, cable 508, which has been in contact with liquefied gas, will be extremely cold, making its handling dangerous.

[0010] Therefore, the present invention provides a pump installation device that can reduce the amount of purge gas used to prevent the release of boil-off gas (BOG) from the pump column when loading a submersible pump into and retrieving it from the pump column, and furthermore, can create a safe working environment. The present invention also provides a method for installing a submersible pump inside a pump column and a method for removing a submersible pump from a pump column using such a pump installation device. [Means for solving the problem]

[0011] In one embodiment, a pump installation device is provided for installing and removing a submersible pump used for transferring liquefied gas from a pump column, the device comprising a work chamber forming a closed workspace, an actuator-driven door covering the upper opening of the pump column, a suspension cable for suspending the submersible pump from the pump column, and a crane for raising and lowering the suspension cable, wherein the upper opening of the pump column, the actuator-driven door, and the crane are located within the workspace.

[0012] In one embodiment, the suspension cable has a plurality of segmented suspension cables and a plurality of connecting links that connect the plurality of segmented suspension cables, and the pump installation device further includes a link operating device that operates the connecting links to cause the connecting links to connect and disconnect the plurality of segmented suspension cables. In one embodiment, the work chamber includes a purge gas inlet port communicating with the work space and a purge gas supply line connected to the purge gas inlet port. In one embodiment, the pump installation device includes a first electrical contact electrically connected to the motor of the submersible pump, a second electrical contact fixed to the pump column and in contact with the first electrical contact, and a power cable electrically connected to the second electrical contact.

[0013] In one embodiment, a method is provided for installing a submersible pump used for transferring liquefied gas within a pump column, comprising the steps of opening an actuator-driven door located within a closed workspace formed by a work chamber, the actuator-driven door being connected to the upper part of the pump column, connecting a suspension cable to the submersible pump within the workspace, and lowering the suspension cable and the submersible pump within the pump column using a crane located within the workspace, wherein the upper opening of the pump column is located within the workspace.

[0014] In one embodiment, the suspension cable has a plurality of segmented suspension cables and a plurality of connecting links that connect the plurality of segmented suspension cables, and the process of lowering the suspension cable and the submersible pump within the pump column is to operate the connecting links with a link operating device to connect the plurality of segmented suspension cables one by one, while lowering the plurality of segmented suspension cables and the submersible pump within the pump column with the crane. In one embodiment, the method further includes the step of supplying a purge gas into the working space and exposing the submersible pump to the purge gas within the working space before bringing the submersible pump into the pump column. In one embodiment, the method further includes the step of bringing a first electrical contact electrically connected to the motor of the submersible pump into contact with a second electrical contact fixed to the pump column when the suspension cable and the submersible pump are lowered within the pump column.

[0015] In one embodiment, a method is provided for removing a submersible pump used for transferring liquefied gas from a pump column, comprising the steps of opening an actuator-driven door located in a closed workspace formed by a work chamber, the actuator-driven door being connected to the top of the pump column, raising the suspension cable and the submersible pump within the pump column by lifting a suspension cable connected to the submersible pump with a crane located in the workspace, disconnecting the suspension cable from the submersible pump, and lifting the submersible pump from the pump column into the workspace with the crane, wherein the upper opening of the pump column is located in the workspace.

[0016] In one embodiment, the suspension cable has a plurality of segmented suspension cables and a plurality of connecting links that connect the plurality of segmented suspension cables, and the step of raising the suspension cable and the submersible pump within the pump column is to operate the connecting links with a link operating device to disconnect the plurality of segmented suspension cables one by one, while raising the plurality of segmented suspension cables and the submersible pump within the pump column with the crane. In one embodiment, the method further includes the step of lifting the submersible pump from the pump column into the working space, and then supplying a purge gas into the working space to expose the submersible pump to the purge gas within the working space. In one aspect, the method further includes disconnecting a first electrical contact electrically connected to the motor of the submersible pump from a second electrical contact fixed to the pump column when the suspension cable and the submersible pump are raised within the pump column.

Advantages of the Invention

[0017] According to the present invention, by remotely operating the crane and the actuator-driven door from outside the work chamber, the installation of the submersible pump on the pump column and the lifting from the pump column can be automatically performed. Therefore, the operator is not exposed to a dangerous atmosphere. Further, since the upper opening of the pump column is within a closed working space, boil-off gas (BOG) is not released into the atmosphere. As a result, the amount of purge gas used to prevent the release of boil-off gas (BOG) into the atmosphere can be substantially reduced to zero. Furthermore, when the submersible pump is carried into the pump column, by filling the working space with a gas composed of the same components as the components of the liquefied gas, the entry of a gas containing other components such as air into the pump column can be prevented.

Brief Description of the Drawings

[0018] [Figure 1] FIG. 1 shows an embodiment of a pump system for transferring liquefied gas. [Figure 2] FIGS. 2(a) and 2(b) are views of the first electrical contact and the second electrical contact as seen in the radial direction of the pump column. [Figure 3] FIG. 3 is a cross-sectional view showing an embodiment of the connecting link. [Figure 4] FIGS. 4(a) and 4(b) are diagrams for explaining how the first link mechanism is connected to the second link mechanism by the link operating device. [Figure 5] FIGS. 5(a) and 5(b) are diagrams for explaining how the first link mechanism is disconnected from the second link mechanism by the link operating device. [Figure 6] FIG. 6 is a top view showing an embodiment of the support plate. [Figure 7] It is a diagram showing the state before the suspension cable and the submersible pump are carried into the pump column. [Figure 8] It is a diagram explaining an embodiment of a method for installing a submersible pump in a pump column. [Figure 9] It is a diagram explaining an embodiment of a method for installing a submersible pump in a pump column. [Figure 10] It is a diagram explaining an embodiment of a method for installing a submersible pump in a pump column. [Figure 11] It is a diagram explaining an embodiment of a method for installing a submersible pump in a pump column. [Figure 12] It is a diagram explaining an embodiment of a method for installing a submersible pump in a pump column. [Figure 13] It is a diagram explaining an embodiment of a method for installing a submersible pump in a pump column. [Figure 14] It is a diagram explaining an embodiment of a method for removing a submersible pump from a pump column. [Figure 15] It is a diagram explaining an embodiment of a method for removing a submersible pump from a pump column. [Figure 16] It is a diagram explaining an embodiment of a method for removing a submersible pump from a pump column. [Figure 17] It is a diagram explaining an embodiment of a method for removing a submersible pump from a pump column. [Figure 18] It is a diagram explaining an embodiment of a method for removing a submersible pump from a pump column. [Figure 19] It 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. [Figure 20] It is a diagram explaining the operation of carrying a pump into a pump column and the operation of pulling up a pump from a pump column.

Embodiments for Carrying out the Invention

[0019] 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.

[0020] 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, and a head plate 10 that closes the upper opening of the pump column 3. 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 pump column 3 has a purge gas introduction port 8 and a discharge port 9. The discharge port 9 is connected to a transfer pipe (not shown) that extends from the inside to the outside of the liquefied gas storage tank 5.

[0021] 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).

[0022] The head plate 10 is located at the upper end of the pump column 3. The head plate 10 is covered by an actuator-driven door 12. The suspension cable 23 and connecting structure 28 are suspended from the head plate 10. The suspension cable 23 extends vertically within the pump column 3. The suspension cable 23 has multiple segmented suspension cables 23B connected by connecting links 24.

[0023] The connecting structure 28 is attached to the submersible pump 2. The connecting structure 28 is connected to the lower end of the suspension cable 23. More specifically, the connecting structure 28 comprises a link mechanism 28A connected to the suspension cable 23 and a connecting member 28B connecting the link mechanism 28A and the submersible pump 2. The connecting member 28B may be a cable, a rod-shaped member, or the like. The link mechanism 28A has a wider width than the connecting member 28B.

[0024] An electrical terminal 35 is attached to the side wall of the liquefied gas storage tank 5. This electrical terminal 35 is connected to a power source (not shown). The submersible pump 2 has a first electrical contact 21 fixed to its motor 2a, and a second electrical contact 22 that contacts the first electrical contact 21 is provided on the side wall of the pump column 3. A power cable 36 for supplying power to the motor 2a of the submersible pump 2 extends from the electrical terminal 35 to the second electrical contact 22.

[0025] The first electrical contact 21 is fixed to the outer surface of the submersible pump 2 and protrudes radially outward from the outer surface of the submersible pump 2. The second electrical contact 22 is located radially outward from the submersible pump 2. The first electrical contact 21 is movable integrally with the submersible pump 2, while the position of the second electrical contact 22 is fixed. Part of the second electrical contact 22 is located outside the pump column 3, and the entire power cable 36 is located outside the pump column 3. The second electrical contact 22 extends through the side wall of the pump column 3. Thus, the second electrical contact 22 has an outer portion located outside the pump column 3 and an inner portion located inside the pump column 3. The end of the power cable 36 is connected to the outer portion of the second electrical contact 22.

[0026] The first electrical contact 21 and the second electrical contact 22 are in contact with the liquefied gas, but the liquefied gas used in this embodiment has electrical insulating properties. Therefore, no leakage current occurs through the first electrical contact 21 and the second electrical contact 22.

[0027] Although not shown in the figures, in other embodiments, the entire second electrical contact 22 may be located inside the pump column 3, and the power cable 36 may extend through the side wall of the pump column 3 to the second electrical contact 22.

[0028] The first electrical contact 21 is movable together with the submersible pump 2 and is also movable relative to the second electrical contact 22. The first electrical contact 21 can make contact with the second electrical contact 22 when the submersible pump 2 is lowered within the pump column 3. When the submersible pump 2 is lowered to its operating position within the pump column 3 (the position of the submersible pump 2 shown in Figure 1), the first electrical contact 21 makes contact with the second electrical contact 22. This establishes an electrical connection between the first electrical contact 21 and the second electrical contact 22. Power is supplied from the power cable 36 to the motor 2a of the submersible pump 27 via the second electrical contact 22 and the first electrical contact 21, thereby operating the submersible pump 2.

[0029] Figure 2(a) shows the first electrical contact 21 and the second electrical contact 22 as viewed from the radial direction of the pump column 3. The first electrical contact 21 has a first contact surface 21a that extends along the longitudinal direction of the pump column 3. Similarly, the second electrical contact 22 has a second contact surface 22a that extends along the longitudinal direction of the pump column 3. In this embodiment, the first electrical contact 21 has a flat plate shape, and the second electrical contact 22 has a clamp shape that sandwiches the first electrical contact 21. In one embodiment, the second electrical contact 22 may have a flat plate shape, and the first electrical contact 21 may have a clamp shape that sandwiches the second electrical contact 22.

[0030] As shown in Figure 2(b), the first electrical contact 21 can be moved toward the second electrical contact 22 until the first contact surface 21a contacts the second contact surface 22a. The first contact surface 21a and the second contact surface 22a are parallel to each other and extend in the longitudinal direction of the pump column 3. Therefore, the first electrical contact 21 and the second electrical contact 22 are movable relative to each other in the longitudinal direction of the pump column 3 while in contact with each other.

[0031] Returning to Figure 1, during operation of the submersible pump 2, the liquefied gas in the liquefied gas storage tank 5 is introduced into the pump column 3 through the suction valve 6, and the pump column 3 is filled 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 and a transfer pipe (not shown). During operation of the submersible pump 2, the purge gas introduction port 8 is closed by a valve (not shown).

[0032] Next, a pump installation device for installing the submersible pump 2 in and removing it from the pump column 3 will be described. The pump system includes the pump installation device described below. The pump installation device includes a work chamber 1 that forms a closed work space 15, an actuator-driven door 12 that covers the upper opening 3a of the pump column 3, a suspension cable 23 for suspending the submersible pump 2 inside the pump column 3, a crane 40 for raising and lowering the suspension cable 23, and the first electrical contact 21 and the second electrical contact 22. The upper opening 3a of the pump column 3, the actuator-driven door 12, and the crane 40 are located within the work space 15. The work chamber 1 has a work door 16 for bringing the submersible pump 2, suspension cable 23, etc. into and out of the work space 15. This work door 16 is normally closed.

[0033] The work chamber 1 is fixed to the upper wall 5A of the liquefied gas storage tank 5. The work chamber 1 is equipped with a purge gas inlet port 17 and a gas outlet port 18 that communicate with its work space 15. 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.

[0034] 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.

[0035] 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.

[0036] The actuator-driven door 12 is connected to the top of the pump column 3. The actuator-driven door 12 covers the upper opening 3a of the pump column 3 and the head plate 10 that closes this upper opening 3a. The actuator-driven door 12 is equipped with an actuator 13, such as an electric motor or an air cylinder. The actuator-driven door 12 is configured to open and close in response to command signals transmitted from outside the work chamber 1. During operation of the submersible pump 2, the actuator-driven door 12 is closed, as shown in Figure 1.

[0037] When the actuator-driven door 12 is closed, a sealed space is formed between the actuator-driven door 12 and the top of the pump column 3. The head plate 10 is located within this sealed space. The actuator-driven door 12 can prevent boil-off gas (BOG) that has passed through the small gap between the head plate 10 and the top of the pump column 3 from leaking into the working space 15 of the work chamber 1.

[0038] The crane 40 is configured to be movable within the work space 15. More specifically, the crane 40 is movable on support rails 41 located within the work space 15, as indicated by the arrows. The crane 40 can move between a position above the pump column 3 and a position away from the pump column 3. The crane 40 includes a gripping mechanism 44, a wire 45 that suspends the gripping mechanism 44, and a hoisting machine 46 that pays out and retracts the wire 45. The gripping mechanism 44 is configured to grip the head plate 10, the suspension cable 23, the connecting link 24, the connecting structure 28, etc. Examples of the hoisting machine 46 include a hoist and a winch. The crane 40 is configured to operate in response to command signals transmitted from outside the work chamber 1.

[0039] The suspension cable 23 includes multiple segmented suspension cables 23B and multiple connecting links 24 that connect these segmented suspension cables 23B. In Figure 1, only one connecting link 24 is shown. The length of each segmented suspension cable 23B is shorter than the length of the pump column 3. The multiple segmented suspension cables 23B are connected in series by the connecting links 24.

[0040] The pump installation device further includes a link operating device 50 that operates each connecting link 24 to connect and disconnect the divided suspension cables 23B, a support plate 55 that supports the link operating device 50, and a plate actuator 58 that moves the support plate 55 between a position directly above the pump column 3 and a retracted position. The link operating device 50 is positioned on the support plate 55, and the support plate 55 is connected to the plate actuator 58. The plate actuator 58 is capable of moving the link operating device 50 and the support plate 55 together. Furthermore, the link operating device 50 has an actuator 52 such as a linear motor or an air cylinder, and the link operating device 50 is configured to be movable on the support plate 55. That is, the link operating device 50 is movable relative to the support plate 55.

[0041] The link operating device 50 has an operating pin 51 that protrudes toward the connecting link 24. When the connecting link 24 is operated by this operating pin 51, the connecting link 24 is configured to connect or disconnect the split suspension cable 23B.

[0042] Figure 3 is a cross-sectional view showing one embodiment of the connecting link 24. As shown in Figure 3, the connecting link 24 comprises a first link mechanism 62 and a second link mechanism 63. The first link mechanism 62 and the second link mechanism 63 are connected to both ends of each segment suspension cable 23B. In the embodiment shown in Figure 3, the first link mechanism 62 is connected to the lower end of each segment suspension cable 23B, and the second link mechanism 63 is connected to the upper end of each segment suspension cable 23B. The second link mechanism 63 has a wider width than the first link mechanism 62. The link mechanism 28A of the connecting structure 28 shown in Figure 1 has the same configuration as the second link mechanism 63, so the following description also applies to the link mechanism 28A of the connecting structure 28.

[0043] The first link mechanism 62 has a horizontally extending first horizontal hole 62a. The second link mechanism 63 comprises a housing 66 having a recess 65 in which the first link mechanism 62 is housed, and a connecting pin 68 housed in a second horizontal hole 67 formed in the housing 66. The connecting pin 68 is movable within the second horizontal hole 67. The second horizontal hole 67 penetrates the housing 66 horizontally. The diameter of the first horizontal hole 62a of the first link mechanism 62 is larger than the diameter of the connecting pin 68, so the connecting pin 68 can pass through the first horizontal hole 62a of the first link mechanism 62.

[0044] As shown in Figure 3, when the connecting pin 68 is positioned across the first lateral hole 62a of the first link mechanism 62, the first link mechanism 62 and the second link mechanism 63 are connected. On the other hand, when the connecting pin 68 is outside the first lateral hole 62a of the first link mechanism 62, the first link mechanism 62 is disconnected from the second link mechanism 63.

[0045] Figures 4(a) and 4(b) illustrate how the link operating device 50 connects the first link mechanism 62 to the second link mechanism 63. As shown in Figure 4(a), when the connecting pin 68 is located outside the recess 65, the first link mechanism 62 enters the recess 65 of the second link mechanism 63. With the first lateral hole 62a of the first link mechanism 62 and the second lateral hole 67 of the second link mechanism 63 aligned in a straight line, as shown in Figure 4(b), the link operating device 50 moves toward the second link mechanism 63 of the connecting link 24, and the operating pin 51 of the link operating device 50 pushes the connecting pin 68 into the first lateral hole 62a. The connecting pin 68 moves into the first lateral hole 62a, thereby connecting the first link mechanism 62 and the second link mechanism 63.

[0046] Figures 5(a) and 5(b) illustrate how the link operating device 50 disconnects the first link mechanism 62 from the second link mechanism 63. As shown in Figure 5(a), the link operating device 50 moves toward the second link mechanism 63 of the connecting link 24, and the operating pin 51 of the link operating device 50 pushes the connecting pin 68 out of the first horizontal hole 62a. Then, as shown in Figure 5(b), the operating pin 51 of the link operating device 50 is pulled out from the first horizontal hole 62a and the second horizontal hole 67, and the first link mechanism 62 is disconnected from the second link mechanism 63.

[0047] Figure 6 is a top view showing one embodiment of the support plate 55 shown in Figure 1. The support plate 55 has a horizontally elongated notch 55a. The width of this notch 55a is greater than the width of the split suspension cable 23B and the width of the connecting member 28B of the connecting structure 28, but smaller than the width of the second link mechanism 63 of the connecting link 24 and the width of the link mechanism 28A of the connecting structure 28. Therefore, the split suspension cable 23B and the connecting member 28B of the connecting structure 28 can pass through the notch 55a, but the second link mechanism 63 of the connecting link 24 and the link mechanism 28A of the connecting structure 28 cannot pass through the notch 55a.

[0048] Figure 7 shows the state before the suspension cable 23 and the submersible pump 2 are brought into the pump column 3. As shown in Figure 7, the multiple segmented suspension cables 23B that make up the suspension cable 23, and the submersible pump 2 are located away from the pump column 3 in the working space 15 of the work chamber 1. The submersible pump 2 has a connecting structure 28 and a first electrical contact 21 pre-attached to it. A connecting link 24 is pre-attached to each segmented suspension cable 23B, and a head plate 10 is pre-attached to one of the segmented suspension cables 23B. The valve body 6A of the suction valve 6 is pressed against the lower end of the pump column 3 by multiple springs 6B, closing the lower opening of the pump column 3.

[0049] Next, an embodiment of a method for installing the submersible pump 2 inside the pump column 3 will be described with reference to Figures 7 to 13. The series of operations shown in Figures 7 to 13 include lowering the submersible pump 2 inside the pump column 3 and connecting the multiple segmented suspension cables 23B one by one to the suspension cable 23. Before the operations described below, liquefied gas is discharged from the pump column 3. Specifically, with the actuator-driven door 12 open, purge gas is supplied into the working space 15 through the purge gas inlet port 17, increasing the pressure inside the pump column 3, thereby discharging the liquefied gas from the pump column 3 through the suction valve 6. After that, the actuator-driven door 12 is closed.

[0050] In step 101, as shown in Figure 7, with the upper opening 3a of the pump column 3 closed by the actuator-driven door 12, the working space 15 within the work chamber 1 housing the submersible pump 2 is evacuated through the gas outlet port 18. Then, a purge gas (for example, containing an inert gas and / or a gas with the same components as the liquefied gas) is supplied to the working space 15 from the purge gas inlet port 17, filling the working space 15 with the purge gas. The submersible pump 2 is exposed to (contacted by) the purge gas within the working space 15, 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 working space 15 and the supply of purge gas to the working space 15 may be repeated.

[0051] In step 102, the actuator-driven door 12 is opened, and the crane 40 transports the submersible pump 2 to an upper position above the pump column 3. More specifically, the gripping mechanism 44 of the crane 40 grips the link mechanism 28A of the connecting structure 28 connected to the submersible pump 2, and the crane 40 transports the submersible pump 2 and the connecting structure 28 together to an upper position above the pump column 3. In step 103, the crane 40 lowers the submersible pump 2 and the connecting structure 28 together, moving the submersible pump 2 into the pump column 3, while positioning the link mechanism 28A of the connecting structure 28 above the pump column 3.

[0052] In step 104, with the link mechanism 28A of the connecting structure 28 positioned above the pump column 3, the plate actuator 58 (see Figure 1) moves the support plate 55 and the link operating device 50 toward the pump column 3, so that the support plate 55 covers the upper opening 3a of the pump column 3. As described with reference to Figure 6, the support plate 55 has a notch 55a, the width of which is greater than the width of the connecting member 28B of the connecting structure 28 and less than the width of the link mechanism 28A. In step 104 shown in Figure 8, the support plate 55 moves toward the pump column 3 so that the connecting member 28B is positioned within the notch 55a of the support plate 55.

[0053] In step 105, the crane 40 further lowers the connecting structure 28 and the submersible pump 2 until the link mechanism 28A of the connecting structure 28 contacts the support plate 55. The submersible pump 2 is suspended from the support plate 55 by the connecting structure 28. That is, the load of the submersible pump 2 is supported by the support plate 55. In step 106, the gripping mechanism 44 of the crane 40 releases the link mechanism 28A of the connecting structure 28, and then the crane 40 transports one of the pre-prepared divided suspension cables 23B (see Figure 7) to an upper position above the pump column 3. The second link mechanism 63 of the connecting link 24 is pre-attached to the upper end of the divided suspension cable 23B, and the first link mechanism 62 of the connecting link 24 is pre-attached to the lower end of the divided suspension cable 23B.

[0054] In step 107, the split suspension cable 23B is lowered by the crane 40 until the first link mechanism 62, which is attached to the lower end of the split suspension cable 23B, enters the recess 65 (see Figure 4(a)) of the link mechanism 28A on the support plate 55. In step 108, the link operating device 50 moves toward the link mechanism 28A on the support plate 55, and the operating pin 51 of the link operating device 50 moves the connecting pin 68 of the link mechanism 28A into the first horizontal hole 62a (see Figure 4(b)). As a result, the first link mechanism 62 is connected to the link mechanism 28A, and the split suspension cable 23B is connected to the connecting structure 28.

[0055] In step 109, the link operating device 50 moves away from the link mechanism 28A until its operating pin 51 is positioned outside the link mechanism 28A. The crane 40 then slightly lifts the split suspension cable 23B, the connecting structure 28, and the submersible pump 2. The load of the submersible pump 2 is supported by the crane 40. In step 110, the plate actuator 58 (see Figure 1) moves the support plate 55 and the link operating device 50 away from the pump column 3. Subsequently, the crane 40 lowers the split suspension cable 23B, the connecting structure 28, and the submersible pump 2, moving the submersible pump 2 into the pump column 3, while positioning the second link mechanism 63 of the connecting link 24 above the pump column 3.

[0056] In step 111, before the second link mechanism 63, which is attached to the uppermost split suspension cable 23B, enters the pump column 3, the plate actuator 58 (see Figure 1) moves the support plate 55 and the link operating device 50 toward the pump column 3, so that the support plate 55 covers the upper opening 3a of the pump column 3. As described with reference to Figure 6, the width of the notch 55a in the support plate 55 is greater than the width of the split suspension cable 23B and less than the width of the second link mechanism 63. In step 111 shown in Figure 11, the support plate 55 moves toward the pump column 3 so that the split suspension cable 23B is positioned within the notch 55a of the support plate 55.

[0057] In step 112, the crane 40 further lowers the segmented suspension cable 23B, the connecting structure 28, and the submersible pump 2 within the pump column 3 until the second link mechanism 63, attached to the uppermost segmented suspension cable 23B, contacts the support plate 55. The submersible pump 2 is suspended from the support plate 55 by the segmented suspension cable 23B and the connecting structure 28. In other words, the load of the submersible pump 2 is supported by the support plate 55.

[0058] Then, the same steps as those described in steps 106 to 112 above are repeated until the submersible pump 2 approaches the bottom of the pump column 3, while adding the remaining segments of the multiple segmented suspension cables 23B one by one. That is, the connecting link 24 is operated by the link operating device 50 to connect the multiple segmented suspension cables 23B one by one, while the crane 40 lowers the multiple segmented suspension cables 23B and the submersible pump 2 inside the pump column 3.

[0059] In step 113, 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. The head plate 10 is pre-attached to the upper end of this last segmented suspension cable 23B. In step 114, as described with reference to Figures 4(a) and 4(b), the first link mechanism 62 attached to the lower end of the uppermost split suspension cable 23B is connected to the second link mechanism 63 on the support plate 55.

[0060] In step 115, the plate actuator 58 (see Figure 1) moves the support plate 55 and the link operating device 50 away from the pump column 3. Subsequently, the crane 40 lowers the split suspension cable 23B, the connecting structure 28, and the submersible pump 2, closing the upper opening 3a of the pump column 3 with the head plate 10, and placing the submersible pump 2 on the suction valve 6. The suction valve 6 opens due to the weight of the submersible pump 2. At the same time, the first electrical contact 21 fixed to the submersible pump 2 makes contact with the second electrical contact 22 fixed to the pump column 3, thereby establishing an electrical connection between the motor 2a of the submersible pump 2 and the power cable 36.

[0061] In step 116, the gripping mechanism 44 of the crane 40 separates from the head plate 10, and the actuator-driven door 12 closes. This completes the installation of the submersible pump 2 onto the pump column 3.

[0062] The worker can automatically install the submersible pump 2 onto the pump column 3 by remotely operating the crane 40, link operating device 50, and actuator-driven door 12 from outside the work chamber 1. Therefore, the worker is not exposed to a hazardous atmosphere. In addition, since the upper opening 3a of the pump column 3 is located within the closed work space 15, boil-off gas (BOG) is not released into the atmosphere. As a result, the amount of purge gas used to prevent the release of boil-off gas (BOG) into the atmosphere can be reduced to virtually zero. Furthermore, when the submersible pump 2 is loaded onto the pump column 3, the work space 15 is filled with a gas consisting of the same components as the liquefied gas, thereby preventing gases containing other components such as air from entering the pump column 3.

[0063] Next, an embodiment of a method for removing the submersible pump 2 from the pump column 3 will be described with reference to Figures 1, 14 to 18. In removing the submersible pump 2, the steps described with reference to Figures 7 to 13 are basically performed in the reverse order. The series of operations shown in Figures 1, 14 to 18 include raising the submersible pump 2 within the pump column 3 and detaching the multiple segmented suspension cables 23B one by one from the suspension cable 23.

[0064] In step 201, as shown in Figure 1, with the upper opening 3a of the pump column 3 closed by the head plate 10 and the actuator-driven door 12, the working space 15 in the work chamber 1 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 into the working space 15 from the purge gas inlet port 17, filling the working space 15 with purge gas. The evacuating of the working space 15 and the supply of purge gas to the working space 15 may be repeated.

[0065] In step 202, the actuator-driven door 12 is opened as shown in Figure 14. Next, the gripping mechanism 44 of the crane 40 grips the head plate 10, and the crane 40 slightly lifts the head plate 10, the split suspension cable 23B, the connecting structure 28, and the submersible pump 2, and closes the suction valve 6. When the submersible pump 2 is lifted from its operating position (the position of the submersible pump 2 shown in Figure 1), the first electrical contact 21 is disconnected from the second electrical contact 22, thereby cutting off the electrical connection between the motor 2a of the submersible pump 2 and the power cable 36. Furthermore, purge gas is supplied into the work chamber 1 through the purge gas inlet port 17, increasing the pressure inside the pump column 3. As the pressure inside the pump column 3 increases, liquefied gas is discharged from the pump column 3 through the suction valve 6.

[0066] In step 203, the crane 40 lifts the multiple segmented suspension cables 23B, the connecting structure 28, and the submersible pump 2 until the entire uppermost segmented suspension cable 23B is positioned above the pump column 3. Then, the plate actuator 58 (see Figure 1) moves the support plate 55 and the link operating device 50 toward the pump column 3, and the support plate 55 covers the upper opening 3a of the pump column 3.

[0067] In step 204, the crane 40 lowers the split suspension cable 23B, the connecting structure 28, and the submersible pump 2 slightly until the second link mechanism 63, which is directly above the support plate 55, makes contact with the support plate 55. The submersible pump 2 is suspended from the support plate 55 by the split suspension cable 23B and the connecting structure 28. In other words, the load of the submersible pump 2 is supported by the support plate 55.

[0068] In step 205, the link operating device 50 moves toward the second link mechanism 63 on the support plate 55, and the operating pin 51 of the link operating device 50 moves the connecting pin 68 of the second link mechanism 63 out of the first lateral hole 62a (see Figure 5(a)). In step 206, the link operating device 50 separates from the second link mechanism 63 on the support plate 55 (see Figure 5(b)). This disconnects the first link mechanism 62 from the second link mechanism 63, allowing the uppermost split suspension cable 23B to be disconnected from the other split suspension cables 23B.

[0069] In step 207, the crane 40 lifts the uppermost segmented suspension cable 23B and moves it to a position further away from the pump column 3 (see Figure 7). In step 208, the crane 40 grips the second link mechanism 63 on the support plate 55.

[0070] Then, the same steps as those in steps 203 to 207 above are repeated by the crane 40, removing the multiple segmented suspension cables 23B one by one, until all of the segmented suspension cables 23B are removed. That is, the connecting link 21 is operated by the link operating device 50 to disconnect the multiple segmented suspension cables 23B one by one, while the crane 40 raises the multiple segmented suspension cables 23B and the submersible pump 2 inside the pump column 3. When all of the segmented suspension cables 23B have been removed, the link mechanism 28A of the connecting structure 28 attached to the submersible pump 2 is supported by the support plate 55.

[0071] In step 209, the gripping mechanism 44 grips the link mechanism 28A of the connecting structure 28, and the crane 40 slightly lifts the connecting structure 28 and the submersible pump 2. Subsequently, the plate actuator 58 (see Figure 1) moves the support plate 55 and the link operating device 50 away from the pump column 3. In step 210, the crane 40 lifts the entire connecting structure 28 and submersible pump 2 from the pump column 3 and transports them to a location further away from the pump column 3 (see Figure 7). In step 211, the actuator-driven door 12 is closed.

[0072] In step 212, as shown in Figure 7, a purge gas (for example, an inert gas and / or a gas consisting of the same components as the liquefied gas) is supplied to the working space 15 of the work chamber 1 through the purge gas inlet port 17, filling the working space 15 with the purge gas. The submerged pump 2 is exposed to (contacted with) the purge gas in the purge container 1, thereby heating the submerged pump 2. This step is a hot-up that heats the submerged pump 2. This completes the removal of the submerged pump 2 from the pump column 3.

[0073] The operator can automatically remove the submersible pump 2 from the pump column 3 by remotely operating the crane 40, link operating device 50, and actuator-driven door 12 from outside the work chamber 1. Therefore, the operator is not exposed to a hazardous atmosphere. In addition, since the upper opening 3a of the pump column 3 is located within the closed work space 15, boil-off gas (BOG) is not released into the atmosphere. As a result, the amount of purge gas used to prevent the release of boil-off gas (BOG) into the atmosphere can be reduced to virtually zero. Furthermore, when the submersible pump 2 is lifted from the pump column 3, the work space 15 is filled with a gas consisting of the same components as the liquefied gas, thereby preventing gases containing other components such as air from entering the pump column 3.

[0074] 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]

[0075] 1. Working Chamber 2 Submersible pump 2a electric motor 3 Pump Column 5. Liquefied gas storage tank 6. Suction valve 8. Purge gas introduction port 9 Discharge Ports 10 Headplate 12 Actuator-driven doors 13 Actuators 15. Workspace 16 Work Doors 17. Purge gas inlet port 18 Gas outlet ports 21 First electrical contact 22 Second electrical contact 23 Suspension Cables 23B Split suspension cable 24 Linking Links 28 Connected structure 35 Electrical terminals 36 Power Cables 40 Cranes 41 Support rail 44 Gripping mechanism 45 wires 46. ​​Winding machine 50 Link Operating Device 51 Operating pins 52 Actuators 55 Support plate 58 Plate Actuator 62. First Link Mechanism 62a First horizontal cave 63 Third Link Mechanism 65 Recessed area 66 Housing 67 Second Horizontal Cave 68 Connecting pins 70. Purge gas supply source 71 Purge gas supply line 74 Vacuum Line

Claims

1. 1. A pump installation device for installing and removing a submersible pump used to transport liquefied gas into and from a pump column, comprising: a working chamber forming an enclosed working space; an actuator-driven door covering an upper opening of the pump column; a lifting cable for suspending the submersible pump within the pump column; a crane for raising and lowering the suspension cable; The pump installation device, wherein the pump column top opening, the actuator driven door, and the crane are disposed within the work space.

2. The suspension cable includes a plurality of divided suspension cables and a plurality of connecting links that connect the plurality of divided suspension cables, The pump installation device according to claim 1 , further comprising a link operating device that operates the connecting link to cause the connecting link to perform connection and disconnection of the multiple split suspension cables.

3. 3. The pump installation apparatus according to claim 1, wherein the working chamber is provided with a purge gas inlet port communicating with the working space, and a purge gas supply line connected to the purge gas inlet port.

4. a first electrical contact electrically connected to an electric motor of the submersible pump; a second electrical contact fixed to the pump column and in contact with the first electrical contact; The pump installation apparatus of claim 1 further comprising a power cable electrically connected to the second electrical contact.

5. 1. A method of installing a submersible pump used to transport liquefied gas in a pump column, comprising: opening an actuator-driven door disposed within an enclosed working space defined by a working chamber, the actuator-driven door being coupled to an upper portion of the pump column; connecting a lifting cable to the submersible pump within the working space; lowering the lifting cable and the submersible pump within the pump column by a crane located within the work space; The upper opening of the pump column is disposed within the working space.

6. The suspension cable includes a plurality of divided suspension cables and a plurality of connecting links that connect the plurality of divided suspension cables, 6. The method of claim 5, wherein the step of lowering the lifting cable and the submersible pump within the pump column comprises the step of lowering the multiple split lifting cables and the submersible pump within the pump column by the crane while operating the connecting links with a link operating device to connect the multiple split lifting cables one by one.

7. 7. The method of claim 5 or 6, further comprising providing a purge gas into the working space prior to loading the submersible pump into the pump column to expose the submersible pump to the purge gas within the working space.

8. 6. The method of claim 5, further comprising the step of contacting a first electrical contact electrically connected to an electric motor of the submersible pump with a second electrical contact fixed to the pump column when the lifting cable and the submersible pump are lowered within the pump column.

9. 1. A method for removing a submersible pump used to transport liquefied gas from a pump column, comprising the steps of: opening an actuator-driven door disposed within an enclosed working space defined by a working chamber, the actuator-driven door being coupled to an upper portion of the pump column; a lifting cable connected to the submersible pump is lifted by a crane disposed in the work space, thereby lifting the lifting cable and the submersible pump within the pump column; Disconnecting the lifting cable from the submersible pump; lifting the submersible pump from the pump column into the work space with the crane; The upper opening of the pump column is disposed within the working space.

10. The suspension cable includes a plurality of divided suspension cables and a plurality of connecting links that connect the plurality of divided suspension cables, 10. The method of claim 9, wherein the step of raising the lifting cable and the submersible pump within the pump column comprises the step of raising the multiple split lifting cables and the submersible pump within the pump column by the crane while operating the connecting links with a link operating device to separate the multiple split lifting cables one by one.

11. 11. The method of claim 9 or 10, further comprising the step of supplying a purge gas into the working space after raising the submersible pump from the pump column into the working space to expose the submersible pump to the purge gas within the working space.

12. 10. The method of claim 9, further comprising disconnecting a first electrical contact electrically connected to an electric motor of the submersible pump from a second electrical contact fixed to the pump column when the lifting cable and the submersible pump are raised within the pump column.

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