Submerged pump and method for extracting the same

Abstract

Prevents vaporized gas from diffusing into the atmosphere during maintenance. [Solution] The submerged pump 10 comprises a cylindrical barrel 15 with an open upper end, a pump section 36 that discharges liquefied gas from the barrel 15, an extraction member 40 for extracting the pump section 36 from the upper end of the barrel 15, and a plate-shaped seal section 22 attached to the upper end of the barrel 15. The seal section 22 is provided with an opening 23a through which the extraction member 40 can be inserted, and an ejection section 26 for ejecting inert gas from a gas supply source 7 into the opening 23a.

Description

[Technical field]

[0001] The present invention relates to a submerged pump and a method for extracting a submerged pump. [Background technology]

[0002] Patent Document 1 discloses an ammonia tank discharge pump that discharges liquid ammonia from the tank. This pump includes a barrel inserted into the tank, a foot valve provided at the bottom end of the barrel, and a discharge pump suspended in the barrel. During maintenance, the foot valve is closed by lifting the discharge pump, and then the inside of the barrel is purified by supplying purge gas into the barrel while sucking gas from inside the barrel. Thereafter, the head plate that closes the top end of the barrel is removed, and the discharge pump is removed from the top end of the barrel to suppress the diffusion of ammonia gas outside the barrel (to the atmosphere). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2023-90418 Summary of the Invention [Problem to be solved by the invention]

[0004] It is difficult to completely purify the inside of the barrel by supplying a purge gas. On the other hand, in the pump of Patent Document 1, the dispensing pump is lifted from the lower part of the barrel and extracted from the upper end with the head plate removed, so that the vaporized gas may diffuse to the outside (atmosphere) from the upper end of the barrel, which is widely opened. In other words, the pump of Patent Document 1 has room for improvement in terms of measures against the diffusion of the vaporized gas from inside the barrel.

[0005] An object of the present invention is to prevent vaporized gas from diffusing into the atmosphere during maintenance. [Means for solving the problem]

[0006] One aspect of the present invention includes a cylindrical barrel having a branched discharge portion disposed above a top wall of a tank, the barrel being fixed to the top wall and extending vertically within the tank, and having an open top end; a pump portion disposed within the barrel and discharging liquefied gas within the barrel from the discharge portion; an extraction member attached to the pump portion, extending upward within the barrel, and for extracting the pump portion from the top end of the barrel; Liquid-tight and airtight Attached plate-like Consisting of a substrate A seal portion, substrate for, A through hole is formed along the axis of the barrel. The present invention provides a submerged pump, which is provided with at least an opening through which the extraction member can be inserted, and an ejection portion that ejects an inert gas from a gas supply source into the opening.

[0007] Another aspect of the present invention is a method for extracting a submerged pump, which discharges liquefied gas from a discharge portion of a cylindrical barrel that is fixed to a top wall of a tank and extends vertically within the tank, by a pump portion disposed in the barrel, the discharge portion being disposed above the top wall, the method comprising: Liquid-tight and airtight The installed seal The barrel is provided on the substrate and extends along the axis of the barrel. The present invention provides a method for extracting a submerged pump, which comprises: suspending the pump section via an extracting member attached to the pump section and extending upward within the barrel, while ejecting an inert gas from a gas supply source through an ejection section into an opening; and extracting the pump section from an upper end of the barrel.

[0008] The pump unit is attached to the lower end of an extraction member for extracting it from the upper end of the barrel. Therefore, during maintenance, the pump unit can be lifted to the top of the barrel via the extraction member and extracted from the upper end of the barrel. This extraction operation is performed while inert gas is being sprayed into the opening from the ejection portion of the seal portion. Therefore, the inert gas sprayed into the opening can prevent the vaporized gas from leaking into the atmosphere from the upper end of the barrel and diffusing therein. Effect of the Invention

[0009] In the present invention, it is possible to prevent the vaporized gas from diffusing into the atmosphere during maintenance. [Brief description of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a submerged pump according to a first embodiment of the present invention attached to a tank. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of part II in FIG. [Diagram 3] FIG. 4 is an exploded perspective view of the upper cover, seal portion, and receiving seat at the upper end of the barrel. [Figure 4] FIG. [Diagram 5] FIG. 4 is a cross-sectional view showing a disconnection process during maintenance. [Figure 6] FIG. 11 is a cross-sectional view showing a connecting step in a lifting process during maintenance. [Figure 7] FIG. 4 is a cross-sectional view showing a lifting step in a lifting process during maintenance. [Figure 8] FIG. 4 is a cross-sectional view showing a supporting step in a lifting process during maintenance. [Figure 9] FIG. 13 is a cross-sectional view showing a separation step of the lifting process during maintenance. [Figure 10] FIG. 11 is a cross-sectional view showing a connecting step in a removal process during maintenance. [Figure 11] FIG. 11 is a cross-sectional view showing a removal step in a removal process during maintenance. [Figure 12] FIG. 6 is a cross-sectional view of a submerged pump according to a second embodiment of the present invention attached to a tank. [Figure 13] FIG. 13 is an enlarged cross-sectional view of part XIII in FIG. 12 . [Figure 14] FIG. 4 is a cross-sectional view showing lifting step 1 of the extraction process during maintenance. [Figure 15] FIG. 4 is a cross-sectional view showing lifting step 2 of the extraction process during maintenance. [Figure 16] FIG. 4 is a cross-sectional view showing lifting step 3 of the extraction process during maintenance. [Figure 17] FIG. 11 is a cross-sectional view showing a removal step in a removal process during maintenance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] (First embodiment) Referring to FIG. 1, a submerged pump 10 according to a first embodiment of the present invention is installed on a top wall 2 of a tank 1 and discharges a liquefied gas (liquid) such as ammonia from inside the tank 1 to a specified external facility.

[0013] The submerged pump 10 includes a barrel 15, a pump section 36, and a protective tube (pulling member) 40. The pump section 36 is attached to the lower end of the protective tube 40. The pump section 36 and the protective tube 40 are inserted together into the barrel 15 from above. The submerged pump 10 also includes a receiving seat 45 that is used when the pump section 36 is pulled out from and inserted into the barrel 15.

[0014] The configurations of the barrel 15, the pump portion 36, the protective tube 40, and the receiving seat 45 will be specifically described below.

[0015] The barrel 15 is cylindrical with open top and bottom ends, and extends vertically through the top wall 2 inside the tank 1. The barrel 15 includes a base plate 15a for fixing to the top wall 2, and a part of the upper side of the barrel 15 protrudes above the top wall 2 and is exposed to the atmosphere. The overall length of the barrel 15 is determined according to the overall height of the tank 1, and is, for example, 50 m. The barrel 15 in FIG. 1 is illustrated as a single continuous straight pipe, but is actually formed by connecting multiple straight pipes in a liquid-tight manner. However, the barrel 15 may be formed of a single straight pipe depending on the overall height of the tank 1.

[0016] A cylindrical liquid discharge section 15b, a gas inlet section 15c, and a gas outlet section 15d are branched and connected to a portion of the barrel 15 located above the top wall 2. The liquid discharge section 15b is connected to a delivery pipe 4 connected to downstream equipment. A gate valve 5 is disposed in the delivery pipe 4. The gas inlet section 15c is connected to a gas supply source 7 for supplying an inert gas (e.g., N2 gas) into the barrel 15. The gas outlet section 15d is connected to equipment (not shown) for processing the inert gas and vaporized gas in the barrel 15.

[0017] A foot valve 16 is attached to the lower end of the barrel 15. A first seal portion 22 and a second seal portion 28 are attached to the upper end of the barrel 15 via an upper cover 21.

[0018] The foot valve 16 includes a valve seat 17 and a valve element 18. The valve seat 17 is cylindrical, and is liquid-tightly attached to the lower end of the barrel 15 by bolts. The valve element 18 is disk-shaped and has the same diameter as the flange portion at the lower end of the valve seat 17, and is attached so as to be movable up and down relative to the valve seat 17. As long as the valve element 18 can close the valve seat 17, it may have a diameter different from the outer diameter of the flange portion of the valve seat 17, and may have a shape other than a disk.

[0019] The valve body 18 is provided with a plurality of shaft portions 18a and protruding portions 18b spaced apart in the circumferential direction. The shaft portions 18a penetrate the flange portion of the valve seat 17 and protrude upward. A stopper 19 is attached to the upper end of the shaft portion 18a. A coil spring 20 is disposed between the stopper 19 and the flange portion so as to surround the shaft portion 18a and urge the valve body 18 upward. The protruding portion 18b protrudes upward, and a part of the protruding portion 18b is located within the valve seat 17. When the pump portion 36 is placed on the protruding portion 18b, the valve body 18 separates from the valve seat 17 against the urging force of the coil spring 20 to open the valve (see FIG. 5). When the pump portion 36 separates from the protruding portion 18b, the urging force of the coil spring 20 presses the valve body 18 against the valve seat 17, closing the valve (see FIG. 7).

[0020] 2 and 3, the upper cover 21 is made of an annular metal plate and is attached by bolts to the flange 15e at the upper end of the barrel 15 in a liquid-tight and airtight manner. The center of the opening 21a of the upper cover 21 is located on the axis A. The diameter of the opening 21a is smaller than the outer shape of the pump section 36 and larger than the outer shape of the protective tube 40, and is large enough to allow the connecting section 41a of the protective tube 40, which will be described in detail later, to be inserted therethrough.

[0021] The outer periphery of the upper cover 21 is provided with a plurality of bolt holes 21b for bolting to the barrel 15. The inner periphery of the upper cover 21 is provided with a plurality of bolt holes 21c for bolting the first seal portion 22 and the second seal portion 28. A pair of bolt holes 21d is provided between the bolt holes 21b and 21c for screwing in an eyebolt 49 (see FIG. 10) attached to a lifting wire 48. The bolt holes 21c and 21d are each a non-through, bottomed cylinder with an open upper end and a closed lower end.

[0022] 2 to 4, first seal portion 22 is configured to suppress diffusion of vaporized gas from inside barrel 15 to the outside by a gas curtain. First seal portion 22 is configured of an annular metal plate and includes a base plate 23 that is attached liquid-tight and airtight on upper cover 21.

[0023] The outer diameter of the substrate 23 is smaller than the outer shape of the upper cover 21 and larger than the imaginary diameter corresponding to the position where the bolt hole 21c is formed. More specifically, the outer diameter of the substrate 23 is smaller than the dimension between a pair of bolt holes 21d of the upper cover 21, that is, the imaginary diameter at the position where the bolt hole 21d is formed in the upper cover 21. This allows the bolt hole 21d to be exposed when the first seal portion 22 is placed on the upper cover 21. The substrate 23 is provided with an opening 23a, a bolt through hole 23c, a gas supply portion 24, and a guide protrusion 27.

[0024] The center of the opening 23a is located on the axis A. The diameter of the opening 23a is the same as that of the opening 21a of the upper cover 21. In other words, the diameter of the opening 23a is smaller than the outer shape of the pump section 36 and larger than the outer shape of the protective tube 40, and is large enough to allow the connecting section 41a of the protective tube 40, which will be described in detail later, to be inserted therethrough. The diameter of the opening 23a may be different from the diameter of the opening 21a of the upper cover 21. The lower part of the opening 23a is formed by a conical cylindrical inclined section 23b that widens radially outward as it approaches the lower side.

[0025] The bolt through holes 23c are configured to attach the first seal portion 22 to the upper cover 21. A plurality of bolt through holes 23c are provided at equal intervals on the outer periphery of the first seal portion 22 so as to correspond to the bolt holes 21c of the upper cover 21, and penetrate in the up-down direction.

[0026] The gas supply unit 24 is configured to supply an inert gas (e.g., N2 gas) into the opening 23a. The gas supply unit 24 includes a plurality of passages 25 (four in this embodiment) and a nozzle (ejector) 26 attached to each of the passages 25.

[0027] The passage 25 includes an inlet portion 25a extending in the radial direction of the substrate 23, and an outlet portion 25b communicating with the inlet portion 25a. The inlet portion 25a opens on the outer peripheral surface of the substrate 23 and extends radially inward. A pipe 8 connected to a gas supply source 7 is connected to the outer end of the inlet portion 25a. The outlet portion 25b has a smaller hole diameter than the inlet portion 25a, and opens at an inclined portion 23b so as to face the inside of the opening 23a. The outlet portion 25b is inclined downward from the outer side toward the inner side in the radial direction of the substrate 23.

[0028] The nozzle 26 is attached to the end of the outlet 25b on the opening 23a side. The nozzle 26 ejects the inert gas supplied from the gas supply source 7 through the passage 25 into the opening 23a at a predetermined pressure. More specifically, the nozzle 26 ejects the inert gas obliquely downward with respect to the axis A so as to be inclined downward from the outside to the inside in the radial direction of the barrel 15. The multiple nozzles 26 are disposed at equal intervals in the circumferential direction around the axis A by being attached to the passage 25. It is preferable that the ejection angle of the inert gas from each nozzle 26 is within a range in which the inert gas ejected by the adjacent nozzles 26 overlaps. The number and angle of the nozzles 26 including the passages 25 can be changed as necessary as long as it is within a range in which the vaporized gas in the barrel 15 can be prevented from leaking to the outside and diffusing.

[0029] The guide protrusion 27 is a structure for guiding a pair of divided bodies 46 constituting the receiving seat 45. The guide protrusion 27 is formed by a stud bolt, and is detachably screwed into a bolt hole 23d provided in the base plate 23. In the normal state shown in Figs. 1 and 2, the guide protrusion 27 is removed from the base plate 23. As shown in Figs. 3 and 6 to 11, when the pump unit 36 ​​is pulled out and inserted into the barrel 15, the guide protrusion 27 is attached to the base plate 23. In the attached state to the base plate 23, the guide protrusion 27 protrudes upward from the base plate 23 along the axis A. Two guide protrusions 27 are used for each divided body 46, making a total of four guide protrusions 27. The number of guide protrusions 27 can be changed as necessary as long as it is within a range in which the pair of divided bodies 46 can be guided.

[0030] 2, second seal portion 28 is configured to prevent vaporized gas in barrel 15 from leaking and diffusing to the outside through protective tube 40 under normal conditions. Second seal portion 28 includes a bobbin-shaped base body 29 that is attached onto first seal portion 22 in a liquid-tight and air-tight manner.

[0031] The lower flange portion 29a of the base body 29 is provided with a bolt through hole corresponding to the bolt through hole 23c (see FIG. 3) of the first seal portion 22. The second seal portion 28 and the first seal portion 22 are connected to the upper cover 21 by screwing a bolt that passes through the lower flange portion 29a and the first seal portion 22 into the bolt hole 21c of the upper cover 21.

[0032] The upper flange of the base 29 is provided with bolt through holes for bolting the terminal block 32. A gland packing (not shown) for sealing with the protective tube 40 is attached to the inner periphery between the lower flange 29a and the upper flange.

[0033] 1, a terminal block 32 is attached by bolts to the upper side of the second seal portion 28. A power supply connection portion for supplying power to the pump portion 36 and a control panel for controlling the pump portion 36 are connected to the terminal block 32.

[0034] The pump unit 36 ​​is of an immersion type and is disposed at the lower end of the barrel 15. The pump unit 36 ​​discharges the liquefied gas that has entered the barrel 15 from the liquid discharge unit 15b through the gap between the barrel 15 and the protective tube 40. When the pump unit 36 ​​is disposed in the barrel 15, it presses the valve body 18 downward to open the foot valve 16, and is placed on the valve body 15. The pump unit 36 ​​includes a motor and an impeller (not shown) in a casing. The motor is connected to the terminal block 32 by a cable 37 that is routed in the protective tube 40. The cable 37 is configured by connecting a plurality of electric wires by a connector 38. The cable 37 may be configured by a single electric wire without being connected by the connector 38.

[0035] 1, the protective tube 40, which is an example of a drawing member, is cylindrical as a whole and is configured to protect the cable 37. The protective tube 40 is made of metal and is configured by connecting a plurality of cylindrical bodies 41 in a straight tube shape, and is inserted along the axis A of the barrel 15. The outer diameter of each cylindrical body 41 is the same and is smaller than the inner diameter of the barrel 15, as well as the inner diameter of the opening 21a of the upper cover 21 and the inner diameter of the opening 23a of the first seal part 22. The entire length of each cylindrical body 41 is a length (e.g., 5 m) that can be lifted by a crane (lifting mechanism) not shown. The connectors 38 of the cable 37 described above are attached to the upper and lower ends of the cylindrical bodies 41.

[0036] A connecting portion 41a protruding radially outward is provided at each of the upper and lower ends of the multiple cylindrical bodies 41 except for the lower cylindrical body 41A and the upper cylindrical body 41B. The connecting portion 41a is provided only at the upper end of the cylindrical body 41A, and the pump section 36 is connected to the lower end of the cylindrical body 41A. The connecting portion 41a is provided only at the lower end of the cylindrical body 41B. The multiple cylindrical bodies 41 are connected in a straight pipe shape by overlapping the connecting portions 41a of the vertically adjacent cylindrical bodies 41 and fastening them with bolts.

[0037] The connecting portion 41a is configured by a flange protruding in a circular ring shape relative to the cylindrical body 41. The outer diameter of the connecting portion 41a is smaller than the diameters of the opening 21a of the upper cover 21 and the opening 23a of the first seal portion 22. This allows the connecting portion 41a to pass through the opening 21a of the upper cover 21 and the opening 23a of the first seal portion 22 and be removable from the upper end of the barrel 15 to the outside. As long as the connecting portion 41a is configured to protrude radially outward relative to the cylindrical body 41, it may be an interrupted circular ring shape or may have a shape other than a ring.

[0038] An upper portion of the upper end cylinder 41B penetrates the upper cover 21, the first seal portion 22, and the second seal portion 28 and protrudes upward. Referring to Fig. 6, during maintenance, a connecting member 42 for connecting a wire 48 is attached to the upper end of the cylinder 41B. The connecting member 42 is annular and has an outer diameter larger than the diameters of the opening 21a of the upper cover 21 and the opening 23a of the first seal portion 22. The connecting member 42 is provided with a bolt hole into which an eyebolt 49 of the wire 48 is screwed.

[0039] 6 to 8, receiving seat 45 is used when pulling out and inserting pump section 36 into barrel 15, and is detachably disposed on first seal section 22. Receiving seat 45 is made of metal, and supports pump section 36 in a suspended position via protective tube 40 by holding connecting section 41a at the upper end of cylindrical body 41.

[0040] 2 and 3, the receiving seat 45 is composed of a pair of divided bodies 46 obtained by dividing a bobbin-shaped annular body into two in the circumferential direction as a whole. Each divided body 46 includes a base 46a, a lower support portion 46b provided at the lower end of the base 46a, and an upper support portion 46c provided at the upper end of the base 46a, and is annular in use when the divided bodies are arranged facing each other so that their linear divided edges are in contact with each other. The receiving seat 45 may be composed of three or more divided bodies 46.

[0041] The base 46a is semi-cylindrical with an inner diameter larger than the outer diameter of the main body of the cylindrical body 41 and smaller than the outer diameter of the connecting portion 41a, and is cylindrical by arranging the pair of divided bodies 46 in close proximity to each other. The internal space of the base 46a forms an insertion hole 46d through which the part of the cylindrical body 41 other than the connecting portion 41a can be inserted. A seal portion 46e protruding radially inward toward the protective tube 40 is provided on the inner periphery of the base 46a by joining. The seal portion 46e is semi-annular, and becomes annular by arranging the pair of divided bodies 46 in close proximity to each other. The inner diameter of the seal portion 46e is larger than the outer diameter of the main body of the cylindrical body 41 excluding the connecting portion 41a, but is set as small as possible within the range in which the cylindrical body 41 can be inserted.

[0042] The lower support portion 46b is joined to the lower end of the base portion 46a. The lower support portion 46b is semicircular, and is formed into a circular shape by arranging the pair of divided bodies 46 facing each other in close proximity. The outer diameter of the lower support portion 46b is larger than the diameter of the opening 23a of the first seal portion 22 and smaller than the outer diameter of the first seal portion 22. The lower support portion 46b is provided with a pair of guide grooves 46f extending from the outer periphery toward the divided edge. The pair of guide grooves 46f extend parallel to the direction perpendicular to the divided edge. By inserting the guide protrusions 27 of the first seal portion 22 into these guide grooves 46f, the pair of divided bodies 46 can be guided in the approaching and separating directions, that is, the direction in which they approach each other (inward in the radial direction) and the direction in which they separate from each other (outward in the radial direction). When the pair of divided bodies 46 are separated from each other, the connecting portion 41a of the protective tube 40 can be inserted into the insertion hole 46d. When the pair of divided bodies 46 are brought close to each other, the connecting portion 41a of the protective tube 40 cannot be inserted through the insertion hole 46d.

[0043] The upper support portion 46c is joined to the upper end of the base portion 46a. The upper support portion 46c is semicircular, and is formed by arranging the pair of divided bodies 46 facing each other in close proximity. The outer diameter of the upper support portion 46c is larger than the outer diameter of the connecting portion 41a of the cylindrical body 41 and smaller than the outer diameter of the lower support portion 46b. The outer diameter of the upper support portion 46c is large enough to expose the guide groove 46f. A plurality of reinforcing ribs 46g are provided between the upper support portion 46c and the lower support portion 46b at intervals in the circumferential direction. The ribs 46g are joined to the base portion 46a, the lower support portion 46b, and the upper support portion 46c, respectively.

[0044] Next, a method for pulling out the pump portion 36 of the submerged pump 10 from the barrel 15 during maintenance will be described.

[0045] The method for extracting the submerged pump 10 of this embodiment includes a shutoff process shown in FIG. 5, a lifting process shown in FIGS. 6 to 9, and an extraction process shown in FIGS.

[0046] In the shutoff process, the gate valve 5 shown in Fig. 1 is switched from an open state to a closed state. Also, as shown in Fig. 5, the terminal block 32 is removed from the second seal portion 28, and the connection of the cable 37 is released.

[0047] Next, in the lifting step, the gas supply source 7 is operated to start supplying the inert gas to the gas inlet portion 15c and the first seal portion 22. This purifies the inside of the barrel 15 (purging step) and suppresses the diffusion of the vaporized gas from the opening 21a of the upper cover 21 to the outside (diffusion suppression step). In the lifting step, in parallel with the purging step and the diffusion suppression step, the connecting step shown in Fig. 6, the lifting step shown in Fig. 7, the supporting step shown in Fig. 8, and the separating step shown in Fig. 9 are repeatedly performed until the connecting portion 41a of the lower end cylinder 41A is exposed.

[0048] Specifically, when lifting the upper end (first from the top) cylindrical body 41B, in the connecting step shown in FIG. 6, first, the bolt of the lower flange portion 29a of the second seal portion 28 is removed, and the connection between the first seal portion 22 and the second seal portion 28 and the upper cover 21 is released. Next, the second seal portion 28 is removed from the cylindrical body 41B. After that, a pair of divided bodies 46 is placed on the first seal portion 22 on which the guide protrusions 27 (see FIG. 3) are arranged. In addition, the connecting member 42 is attached to the upper end of the cylindrical body 41B, and the eye bolt 49 attached to the tip of the wire 48 is screwed into the connecting member 42.

[0049] 7, the wire 48 is pulled up by a crane to lift up the pump section 36 via the protective tube 40. This separates the pump section 36 from the valve body 18 and closes the foot valve 16. When the connecting portion 41a at the upper end of the second cylinder 41 connected to the first cylinder 41B becomes exposed above the first seal portion 22, more specifically, above the receiving seat 45, the lifting of the wire 48 by the crane is stopped.

[0050] 8, the pair of divided bodies 46 are moved toward each other along the guide grooves 46f (see FIG. 3) to cover the opening 23a of the first seal portion 22 with the receiving seat 45. Then, the wire 48 is pulled down by the crane to place the connecting portion 41a of the second cylindrical body 41 on the receiving seat 45. As a result, the pump portion 36 is supported in a suspended state by the receiving seat 45 via the protective tube 40.

[0051] 9, the bolt connecting the connecting portion 41a of the cylindrical bodies 41B, 41 is removed. After that, the wire 48 is pulled up again by the crane, and the connection of the cable 37 by the connector 38 is released. This separates the cylindrical body 41B above the receiving seat 45.

[0052] Next, returning to the connecting step shown in FIG. 6, the second and subsequent cylinders 41 are connected, lifted, supported, and separated repeatedly until the connecting portion 41a of the lower end cylinder 41A is exposed. When the second and subsequent cylinders 41 are lifted, the eyebolt 49 is screwed into the connecting portion 41a of the cylinder 41 located on the receiving seat 45 instead of the connecting member 42, but the other points are the same. During this time, the purging step and the diffusion suppression step are continuously performed. This effectively suppresses the vaporized gas in the barrel 15 from leaking to the outside and diffusing through the opening 21a of the upper cover 21, the opening 23a of the first seal portion 22, and the insertion hole 46d of the receiving seat 45.

[0053] As shown in Fig. 10, the connecting portion 41a of the lower end cylindrical body 41A connected to the pump portion 36 is supported by the receiving seat 45, and the cylindrical body 41 on the receiving seat 45 is separated, and then the extraction process is performed. In the connection step shown in Fig. 10 of the extraction process, the eyebolt 49 is screwed into the bolt hole 21d of the upper cover 21. In addition, the bolt connecting the flange 15e of the barrel 15 to the upper cover 21 is removed. In addition, the gas supply source 7 is stopped, the supply of the inert gas to the gas inlet portion 15c and the first seal portion 22 is stopped, and the connection between the gas supply source 7 and the piping 8 shown in Fig. 1 is released.

[0054] 11, in the extraction step, the wire 48 is pulled up by the crane. As a result, the pump portion 36 is extracted from the upper end of the barrel 15, and the upper cover 21, the first seal portion 22, and the lower end cylinder body 41A are removed together with the pump portion 36.

[0055] On the other hand, when placing the pump unit 36 ​​in the barrel 15 after maintenance, the procedure is reversed from that for removing the pump unit 36 ​​from the barrel 15. That is, the steps of connecting the other cylindrical bodies 41, 41B to the cylindrical bodies 41A, 41 supported by the receiving seat 45 by bolting, and then pulling them down by a crane are repeated. This allows the pump unit 36 ​​to be placed in the barrel 15 installed in the tank 1, as shown in FIG. 1.

[0056] The submerged pump 10 thus configured has the following features.

[0057] The pump section 36 is attached to the lower end of a protective tube 40 in which a plurality of cylindrical bodies 41 are connected in a straight pipe shape, and is disposed integrally with the protective tube 40 inside the barrel 15. Therefore, the pump section 36 can be moved to the upper part of the barrel 15 by repeatedly performing a lifting step of lifting the protective tube 40 and the pump section 36 together, a supporting step of holding the upper end of the cylindrical bodies 41 exposed from the first seal section 22 and supporting the pump section 36 via the protective tube 40, and a separating step of separating the cylindrical bodies 41 above the first seal section 22.

[0058] The lifting step, the supporting step, and the separating step are repeatedly performed while inert gas is sprayed into the opening 23a from the nozzle 26 of the first seal portion 22. Therefore, the inert gas sprayed into the opening 23a can purify the inside of the barrel 15 while suppressing the vaporized gas from leaking into the atmosphere and diffusing. Thereafter, the spraying of the inert gas from the first seal portion 22 is stopped, and a pulling-out step is performed in which the pump portion 36 is pulled out together with the first seal portion 22 from the upper end of the barrel 15, whereby the pump portion 36 can be pulled out from the barrel 15, improving maintainability.

[0059] A plurality of nozzles 26 are provided. Moreover, the plurality of nozzles 26 are provided at equal intervals around the axis. This allows the ejected inert gas to form a gas curtain, so that leakage of vaporized gas from the opening 23a of the first seal portion 22 can be effectively suppressed.

[0060] The pump unit 36 ​​is provided with a receiving seat 45 which is detachably disposed on the first seal portion 22 and supports the pump unit 36 ​​via the protective tube 40 by holding the connecting portion 41a of the cylindrical body 41. This allows the connecting portion 41a at the upper end of the cylindrical body 41 protruding from the upper end of the barrel 15 to be securely held, and the pump unit 36 ​​to be stably suspended via the protective tube 40. Furthermore, the task of separating the cylindrical body 41 above the receiving seat 45 can be easily and stably performed.

[0061] The receiving seat 45 is configured by divided bodies 46 obtained by dividing an annular body into two or more bodies. Therefore, the receiving seat 45 can be easily and reliably disposed so as to surround the outer periphery of the cylindrical body 41 of the protective tube 40 that is lifted up above the first seal portion 22.

[0062] Other embodiments and various modifications of the present invention will be described below, but in these descriptions, points that are not particularly mentioned are the same as those in the first embodiment. In the drawings referred to below, the same elements as those in the first embodiment are given the same reference numerals.

[0063] Second embodiment 12, the submerged pump 10 of the second embodiment differs from the first embodiment in that wires 60, 61 are used as the extraction member instead of the protective tube 40 shown in Fig. 1. In the second embodiment, the pump section 36 can be extracted from the upper end of the barrel 15 by winding up the wires 60, 61 with a winch (winding mechanism) 62 without using the receiving seat 45 of the first embodiment shown in Fig. 1 (see Fig. 17).

[0064] Specifically, the submerged pump 10 of the second embodiment includes a barrel 15 and a pump section 36, similar to the first embodiment. The barrel 15 differs from the submerged pump 10 of the first embodiment only in that the barrel 15 does not include the gas inlet section 15c shown in FIG.

[0065] A foot valve 16 similar to that of the first embodiment is attached to the lower end of the barrel 15. A seal portion (first seal portion) 22 and a closing cover 55 are attached to the upper end of the barrel 15. The upper cover 21 and second seal portion 28 of the first embodiment shown in Fig. 1 are not attached to the upper end of the barrel 15 of the second embodiment.

[0066] 13, similarly to the first embodiment, sealing portion 22 is configured to suppress diffusion of vaporized gas from inside barrel 15 to the outside by a gas curtain. The outer diameter of substrate 23 of sealing portion 22 is the same as the outer diameter of flange 15e at the upper end of barrel 15.

[0067] An opening 23a is provided in the center of the substrate 23. The diameter of the opening 23a is the same as the inner diameter of the barrel 15, and is large enough to insert the pump portion 36. The diameter of the opening 23a may be different from the inner diameter of the barrel 15 as long as it is larger than the outer shape of the pump portion 36.

[0068] The base plate 23 is provided with bolt holes (not shown) for bolting to the flange 15e at the upper end of the barrel 15, similar to the bolt holes 21b of the upper cover 21 shown in Fig. 3. The base plate 23 of the second embodiment is not provided with the bolt through holes 23c and the bolt holes 23d including the guide protrusions 27 of the first embodiment shown in Fig. 3.

[0069] The substrate 23 is provided with a gas supply unit 24 for supplying an inert gas (e.g., N2 gas) into the opening 23a. The gas supply unit 24 includes a plurality of passages 25 (four in this embodiment) and a nozzle 26 attached to each of the passages 25. The passages 25 are formed by one through-hole extending in the radial direction of the substrate 23. The nozzle 26 is attached to the radial inner end of the passage 25, and ejects the inert gas in a direction perpendicular to the axis A (inward in the radial direction).

[0070] The closing cover 55 is made of a metal plate with an outer diameter equal to the outer diameter of the flange 15e at the upper end of the barrel 15, and closes the upper end of the barrel 15 via the seal portion 22. The outer periphery of the closing cover 55 is provided with bolt holes (not shown) for bolting to the flange 15e at the upper end of the barrel 15. The closing cover 55 is placed on the seal portion 22 arranged at the upper end of the barrel 15, and bolts are passed through them and nuts are screwed into them. This allows the closing cover 55 and the seal portion 22 to be attached to the barrel 15 as a single unit.

[0071] The closing cover 55 is provided with a bolt hole 55a for screwing in the eyebolt 49 (see FIG. 15). Also, an insertion hole 55b for inserting the first wire 60 is provided in the center of the closing cover 55. A packing (not shown) is disposed in the insertion hole 55b to provide an airtight seal between the first wire 60 and the insertion hole 55b under normal conditions.

[0072] The closure cover 55 is further provided with an outlet portion 56, a hook portion 57, and a drum 58. The outlet portion 56 is configured to lead out the cable 37 to the outside, and protrudes upward from the closure cover 55. The cable 37 led out from the outlet portion 56 is connected to the terminal block 32 shown in FIG. 1. The hook portion 57 is configured to hook and hold the first wire 60, and protrudes upward from the closure cover 55. The drum 58 is configured to wind and hold the second wire 61, and is provided below the closure cover 55 so as to be located within the barrel 15.

[0073] The wires serving as the extracting members in the second embodiment include a first wire 60 and a second wire 61. The lower ends of these wires 60, 61 are both attached near the center of the upper end of the pump section 36. The wires 60, 61 both extend upward from the pump section 36 inside the barrel 15. The upper end of the first wire 60 is led out to the outside through the insertion hole 55b of the closing cover 55 and is hooked on the hook section 57. The second wire 61 is longer than the first wire 60. The upper end side of the second wire 61 is wound around the drum 58.

[0074] Next, a method for pulling out the pump portion 36 of the submerged pump 10 from the barrel 15 during maintenance will be described.

[0075] The extraction method for the submerged pump 10 of the second embodiment includes an extraction process including the steps shown in FIGS.

[0076] In the lifting step 1 shown in Fig. 14, the gas supply source 7 is operated to start supplying the inert gas to the seal portion 22. This prevents the vaporized gas from diffusing from the insertion hole 55b of the closing cover 55 and the outlet portion 56 to the outside (diffusion prevention step), and further purifies the inside of the barrel 15. In addition, the first wire 60 is connected to a winch 62 and wound up, thereby lifting up the pump portion 36. This separates the pump portion 36 from the valve body 18, and the foot valve 16 closes.

[0077] 15, the first wire 60 is hooked onto the hook portion 57 to hold the pump portion 36 in a suspended state, and the bolts connecting the barrel 15, the seal portion 22, and the closure cover 55 are removed. The eye bolt 49 attached to the tip of the wire 48 is screwed into the closure cover 55, and the closure cover 55 is lifted up by the winch 62 to which the wire 48 is connected. The exposed second wire 61 is then connected to the take-up drum 63 of the winch 62.

[0078] 16, the pump unit 36 ​​is lifted to the top of the barrel 15 by winding up the second wire 61 with the winch 62. At this time, the closure cover 55 to which the eyebolt 49 including the wire 48 is connected is removed from the barrel 15 and is also released from the connection with the winch 62. In addition, the cable 37 and the first wire 60 are pulled out of the closure cover 55, and the portions protruding from the upper end of the barrel 15 due to the lifting of the pump unit 36 ​​are wound up so as not to become entangled.

[0079] 17, the winch 62 continues to wind up the second wire 61, thereby pulling out the pump portion 36 from the upper end of the barrel 15.

[0080] When placing the pump portion 36 in the barrel 15 after maintenance, the procedure for removing the pump portion 36 from the barrel 15 is performed in reverse order.

[0081] In the submerged pump 10 of the second embodiment thus configured, the pump section 36 is attached to the lower end of the wires 60, 61 for pulling out the pump section 36 from the upper end of the barrel 15. Therefore, as in the first embodiment, during maintenance, the pump section 36 can be lifted to the upper part of the barrel 15 via the wires 60, 61 and pulled out from the upper end of the barrel 15. Moreover, this pulling out operation is performed while inert gas is sprayed into the opening 23a from the nozzle 26 of the seal part 22. Therefore, the inert gas sprayed into the opening 23a can prevent the vaporized gas from leaking out of the upper end of the barrel 15 into the atmosphere and diffusing.

[0082] The present invention is not limited to the configurations of the above-described embodiments, and various modifications are possible.

[0083] For example, receiving seat 45 may be formed of one member. Specifically, receiving seat 45 may be configured such that a groove is provided in an annular body including cylindrical base portion 46a and annular support portions 46b and 46c, so as to form a C-shape when viewed from above, through which the portion of tube body 41 other than connecting portion 41a can be inserted.

[0084] In the first embodiment as well, the first seal portion 22 may be directly connected to the flange 15e of the barrel 15 without using the upper cover 21.

[0085] In the first embodiment, water (moisture) may be sprayed as a treatment agent instead of an inert gas into the inlet portion 15c of the barrel 15. In the first embodiment, as in the second embodiment, the barrel 15 may be configured without the inlet portion 15c, and the diffusion suppression step may also serve as the purge step. In the second embodiment, as in the first embodiment, the barrel 15 may be provided with the inlet portion 15c.

[0086] The liquid discharged by the submerged pump 10 is not limited to liquefied gas such as ammonia, and can be changed as necessary. [Explanation of symbols]

[0087] 1 Tank 2. Ceiling 4 Delivery pipe 5. Gate valve 7 Gas supply source 8 Piping 10 Submerged Pump 15 barrels 15a Base plate 15b Liquid drain 15c Gas inlet 15d Gas Outlet 15e flange 16 Foot valve 17 Valve seat 18 Valve body 18a Shaft 18b Projection 19 Stopper 20 Coil spring 21 Upper cover 21a opening 21b Bolt hole 21c Bolt Hole 21d Bolt hole 22 First seal part 23 Substrate 23a opening 23b Slope 23c Bolt Through Hole 23d Bolt hole 24 Gas Supply Section 25 Passage 25a Inlet 25b Outlet 26 Nozzle (jet part) 27 Guide protrusion 28 Second seal part 29 Substrate 29a Lower flange 32 Terminal block 36 Pump section 37 Cable 38 Connectors 40 Protective tube (pulling member) 41 Cylinder 41A Lower end cylinder 41B Upper end of cylinder 41a Connection part 42 Connecting member 45 Receiver 46 Split body 46a base 46b Lower support part 46c Upper support part 46d Through hole 46e Seal part 46f Guide groove 46g Rib 48 Wire 49 Eyebolt 55 Closure cover 55a Bolt hole 55b Insertion hole 56 Derivation part 57 Hook section 58 Drums 60 First Wire 61 Second wire (pulling member) 62 Winch (winding mechanism) 63 Winding drum

Claims

1. a cylindrical barrel having a branched discharge portion disposed above a top wall of the tank, the barrel being fixed to the top wall, extending in a vertical direction within the tank, and having an open upper end; A pump unit disposed in the barrel and configured to discharge the liquefied gas in the barrel through the discharge unit; an extracting member attached to the pump portion and extending upward within the barrel for extracting the pump portion from an upper end of the barrel; a seal portion formed of a plate-shaped base plate attached liquid-tightly and air-tightly to the upper end of the barrel; Equipped with The substrate includes: an opening extending through the barrel along an axis thereof and through which at least the extraction member can be inserted; a jet portion for jetting an inert gas from a gas supply source into the opening; A submerged pump is provided.

2. A submerged pump as described in claim 1, wherein the ejection portion is inclined so as to eject the inert gas diagonally downward with respect to the axis of the barrel.

3. A submerged pump as described in claim 2, wherein the barrel is provided with a gas outlet portion located below the sealing portion for outletting the vaporized gas formed by evaporation of the liquefied gas within the barrel and the inert gas.

4. A submerged pump described in any one of claims 1 to 3, wherein the ejection portions are provided at equal intervals around the axis of the barrel.

5. 4. The submerged pump according to claim 1, wherein the extraction member is a protective tube formed by connecting a plurality of cylindrical bodies in a straight tube shape, inserted into the barrel along the axis of the barrel, and protecting a cable connected to the pump unit.

6. The sealing portion further includes a receiving seat that is removably disposed on the sealing portion, The cylindrical body has a connecting portion protruding in a direction intersecting the axis, 6. The submerged pump according to claim 5, wherein the receiving seat has an insertion hole through which a portion of the cylindrical body other than the connecting portion can be inserted, and the receiving seat is capable of supporting the pump portion via the protective tube by holding the connecting portion.

7. 7. The submerged pump according to claim 6, wherein the receiving seat is constituted by two or more divided bodies obtained by dividing an annular body in the circumferential direction.

8. 4. The submerged pump of claim 1, wherein the extraction member comprises a wire that can be wound up by a winding mechanism.

9. A method for extracting a submerged pump in which a pump unit is disposed in a cylindrical barrel fixed to a top wall of a tank and extending vertically within the tank, and liquefied gas is discharged from a discharge unit of the barrel disposed above the top wall, the method comprising the steps of: A method for extracting a submerged pump, comprising the steps of: spraying an inert gas from a gas supply source from a spray portion into an opening formed on a base plate of a seal portion that is liquid-tight and airtight attached to the upper end of the barrel and penetrating along the axis of the barrel; lifting the pump portion via an extraction member that is attached to the pump portion and extends upward within the barrel; and extracting the pump portion from the upper end of the barrel.

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