Submerged pump and method for drawing submerged pump

Abstract

To suppress diffusion of vaporized gas to the atmosphere during maintenance.SOLUTION: This submerged pump 10 is provided with a cylindrical barrel 15 opened at its upper end, a pump part 36 for discharging liquefied gas in the barrel 15, a pulling-out member 40 for pulling out the pump part 36 from the upper end of the barrel 15, and a plate-like seal part 22 attached to the upper end of the barrel 15. The seal part 22 is provided with an opening part 23a through which the drawing member 40 can be inserted and a jetting part 26 for jetting the inert gas from the gas supply source 7 into the opening part 23a.SELECTED DRAWING: Figure 2

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 attached to the bottom of the barrel, and a discharge pump suspended within the barrel. During maintenance, the discharge pump is lifted up to close the foot valve, and then the inside of the barrel is purified by supplying purge gas into the barrel while sucking gas from within the barrel. Thereafter, the head plate closing the top of the barrel is removed, and the discharge pump is removed from the top of the barrel to prevent ammonia gas from diffusing 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 purge gas. On the other hand, in the pump of Patent Document 1, the head plate is removed, and the dispensing pump is lifted from the bottom of the barrel and removed from the top, so vaporized gas can diffuse from the wide-open top of the barrel to the outside (atmosphere). In other words, the pump of Patent Document 1 has room for improvement in terms of measures to prevent vaporized gas from diffusing 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 provides a submerged pump comprising: a cylindrical barrel having a branched discharge portion located 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 located within the barrel and discharging liquefied gas within the barrel through the discharge portion; an extraction member attached to the pump portion, extending upward within the barrel, for extracting the pump portion from the top end of the barrel; and a plate-shaped seal portion attached to the top end of the barrel, the seal portion having at least an opening through which the extraction member can be inserted, and an ejection portion for ejecting inert gas from a gas supply source into the opening.

[0007] Another aspect of the present invention provides a method for extracting a submerged pump, which has a pump unit arranged inside a cylindrical barrel that is fixed to the top wall of a tank and extends vertically inside the tank, and which discharges liquefied gas from a discharge unit of the barrel that is located above the top wall, the method comprising: spraying inert gas from a gas supply source from a spray unit into an opening of a seal unit attached to the upper end of the barrel; lifting the pump unit via an extraction member that is attached to the pump unit and extends upward inside the barrel; and extracting the pump unit from the upper end of the barrel.

[0008] The pump unit is attached to the lower end of a pull-out member that allows it to be pulled out from the top of the barrel. Therefore, during maintenance, the pump unit can be lifted to the top of the barrel using the pull-out member and pulled out from the top of the barrel. This pulling operation is performed while inert gas is being sprayed into the opening from the nozzle of the seal. Therefore, the inert gas sprayed into the opening prevents vaporized gas from leaking into the atmosphere from the top of the barrel and diffusing. [Effects of the Invention]

[0009] In the present invention, the vaporized gas can be prevented from diffusing into the atmosphere during maintenance. [Brief explanation 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. [Figure 2] FIG. 2 is an enlarged cross-sectional view of part II in FIG. [Figure 3] FIG. 2 is an exploded perspective view of the upper cover, seal, and receiving seat at the upper end of the barrel. [Figure 4] FIG. [Figure 5] FIG. 10 is a cross-sectional view showing a disconnection process during maintenance. [Figure 6] FIG. 10 is a cross-sectional view showing a connecting step in a lifting process during maintenance. [Figure 7] FIG. 10 is a cross-sectional view showing a lifting step in a lifting process during maintenance. [Figure 8] FIG. 10 is a cross-sectional view showing a support step in a lifting process during maintenance. [Figure 9] FIG. 10 is a cross-sectional view showing a separation step of the lifting process during maintenance. [Figure 10] FIG. 10 is a cross-sectional view showing a connecting step in a removal process during maintenance. [Figure 11] FIG. 10 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. [Figure 14] FIG. 1 is a cross-sectional view showing lifting step 1 of the extraction process during maintenance. [Figure 15] FIG. 10 is a cross-sectional view showing lifting step 2 of the extraction process during maintenance. [Figure 16] FIG. 10 is a cross-sectional view showing the lifting step 3 in the extraction process during maintenance. [Figure 17] FIG. 10 is a cross-sectional view showing a removal step in a removal process during maintenance. DETAILED DESCRIPTION OF THE INVENTION

[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 ceiling wall 2 of a tank 1 and discharges a liquefied gas (liquid) such as ammonia from inside the tank 1 to a designated external facility.

[0013] The submerged pump 10 includes a barrel 15, a pump section 36, and a protective tube (extraction 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 inserted into and extracted from 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 within the tank 1, penetrating the top wall 2. The barrel 15 includes a base plate 15a for fixing to the top wall 2, and a portion 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 in reality it is made up of multiple straight pipes connected in a liquid-tight manner. However, depending on the overall height of the tank 1, the barrel 15 may be made up of a single straight pipe.

[0016] A cylindrical liquid discharge portion 15b, a gas inlet portion 15c, and a gas outlet portion 15d are branched and connected to a portion of barrel 15 located above top wall 2. Liquid discharge portion 15b is connected to a delivery pipe 4 connected to downstream equipment. Delivery pipe 4 is provided with a gate valve 5. Gas inlet portion 15c is connected to a gas supply source 7 for supplying an inert gas (e.g., N2 gas) into barrel 15. Gas outlet portion 15d is connected to equipment (not shown) that processes the inert gas and vaporized gas in 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 attached liquid-tight to the lower end of the barrel 15 with 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. The valve element 18 may have a diameter different from the outer diameter of the flange portion of the valve seat 17, or may have a shape other than a disk, as long as it can close the valve seat 17 and close the valve.

[0019] The valve element 18 is provided with a plurality of shaft portions 18a and protrusions 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, surrounding the shaft portion 18a, and biases the valve element 18 upward. The protrusions 18b protrude upward, and a portion of the protrusions 18b is located within the valve seat 17. When the pump portion 36 is placed on the protrusions 18b, the valve element 18 separates from the valve seat 17 against the biasing force of the coil springs 20, opening the valve (see FIG. 5). When the pump portion 36 separates from the protrusions 18b, the biasing force of the coil springs 20 presses the valve element 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 upper cover 21 is provided with a plurality of bolt holes 21b for bolting to barrel 15. The inner periphery of upper cover 21 is provided with a plurality of bolt holes 21c for bolting first seal portion 22 and second seal portion 28. A pair of bolt holes 21d is provided between bolt holes 21b and 21c, into which eyebolts 49 (see FIG. 10) attached to lifting wire 48 are threadedly engaged. 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 use a gas curtain to suppress diffusion of vaporized gas from inside barrel 15 to the outside. First seal portion 22 is configured from an annular metal plate and includes substrate 23 that is attached to upper cover 21 in a liquid-tight and airtight manner.

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

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

[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 the first seal portion 22 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 (four in this embodiment) passages 25 and nozzles (ejectors) 26 attached to the individual 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 at the outer peripheral surface of the substrate 23 and extends radially inward. A pipe 8 connected to the 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 to the inner side in the radial direction of the substrate 23.

[0028] The nozzle 26 is attached to the end of the outlet portion 25b on the opening 23a side. The nozzle 26 sprays 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 sprays the inert gas obliquely downward with respect to the axis A, inclining downward from the outer side to the inner side in the radial direction of the barrel 15. The multiple nozzles 26 are attached to the passage 25 and arranged at equal intervals in the circumferential direction around the axis A. The spray angles of the inert gas from each nozzle 26 are preferably within a range in which the inert gas sprayed by adjacent nozzles 26 overlap. The number and angle of the nozzles 26, including the passages 25, can be changed as needed, as long as the vaporized gas in the barrel 15 is prevented from leaking and diffusing to the outside.

[0029] The guide protrusions 27 are configured to guide the pair of segments 46 that make up the receiving seat 45. The guide protrusions 27 are configured by stud bolts and are detachably screwed into bolt holes 23d provided in the base plate 23. In the normal state shown in FIGS. 1 and 2, the guide protrusions 27 are detached from the base plate 23. As shown in FIGS. 3 and 6 to 11, the guide protrusions 27 are attached to the base plate 23 when the pump unit 36 ​​is pulled out or inserted into the barrel 15. When attached to the base plate 23, the guide protrusions 27 protrude upward from the base plate 23 along the axis A. Two guide protrusions 27 are used for each segment 46, for a total of four guide protrusions 27. The number of guide protrusions 27 can be changed as needed as long as it is possible to guide the pair of segments 46.

[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 liquid-tight and airtight on first seal portion 22.

[0031] The lower flange portion 29a of the base body 29 is provided with bolt through holes corresponding to the bolt through holes 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 threading bolts that pass through the lower flange portion 29a and the first seal portion 22 into the bolt holes 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) is attached to the inner periphery between the lower flange 29a and the upper flange to seal the protective tube 40.

[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 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 disposed within the barrel 15, the pump unit 36 ​​presses the valve element 18 downward to open the foot valve 16, and is then placed on the valve element 15. The pump unit 36 ​​includes a motor and an impeller (not shown) within the casing. The motor is connected to the terminal block 32 by a cable 37 routed within the protective tube 40. The cable 37 is configured by connecting multiple electric wires with a connector 38. The cable 37 may also be configured as a single electric wire without being connected by the connector 38.

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

[0036] Of the multiple cylindrical bodies 41, connecting portions 41a that protrude radially outward are provided at the upper and lower ends, 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 unit 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 connecting portions 41a of vertically adjacent cylindrical bodies 41 are overlapped and bolted together, thereby connecting the multiple cylindrical bodies 41 in a straight pipe shape.

[0037] The connecting portion 41a is configured as a flange that protrudes 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. The connecting portion 41a may be an interrupted circular ring shape or may have a shape other than a ring, as long as it is configured to protrude radially outward relative to the cylindrical body 41.

[0038] The top of the upper cylinder 41B protrudes upward, penetrating the upper cover 21, the first seal portion 22, and the second seal portion 28. Referring to Figure 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 has a bolt hole into which an eyebolt 49 of the wire 48 is threaded.

[0039] 6 to 8, receiving seat 45 is used when inserting and removing pump section 36 from 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 forms an annular shape when in use with the divided bodies 46 facing each other so that their linear divided edges are in contact. The receiving seat 45 may be composed of three or more divided bodies 46.

[0041] The base 46a has a semi-cylindrical shape 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 formed by arranging the pair of segments 46 facing each other and closely together. The internal space of the base 46a forms an insertion hole 46d through which the portion of the cylindrical body 41 other than the connecting portion 41a can be inserted. A seal portion 46e that protrudes radially inward toward the protective tube 40 is provided by welding on the inner periphery of the base 46a. The seal portion 46e has a semi-annular shape, and is formed into an annular shape by arranging the pair of segments 46 facing each other and closely together. 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 that allows the cylindrical body 41 to be inserted therethrough.

[0042] The lower support portion 46b is joined to the lower end of the base portion 46a. The lower support portion 46b has a semicircular ring shape, which is formed by arranging the pair of segments 46 facing each other and 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 has a pair of guide grooves 46f extending from the outer periphery toward the segment edge. The pair of guide grooves 46f extend parallel to and perpendicular to the segment edge. By inserting the guide protrusions 27 of the first seal portion 22 into these guide grooves 46f, the pair of segments 46 can be guided in a direction toward each other (radially inward) and a direction away from each other (radially outward). When the pair of segments 46 are spaced apart, the connecting portion 41a of the protective tube 40 can be inserted through 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 into 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 has a semicircular ring shape, which is formed by arranging the pair of divided bodies 46 facing each other and close to each other. 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 at intervals in the circumferential direction between the upper support portion 46c and the lower support portion 46b. 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 removing 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 step shown in FIG. 5, a lifting step shown in FIGS. 6 to 9, and an extraction step 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 cable 37 is disconnected.

[0047] Next, in the lifting step, the gas supply source 7 is activated to start supplying 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 diffusion of vaporized gas from the opening 21a of the upper cover 21 to the outside (diffusion suppression step). In addition, 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 cylindrical body 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 bolts on the lower flange portion 29a of the second seal portion 28 are 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 are placed on the first seal portion 22 on which the guide protrusions 27 (see FIG. 3) are arranged. Furthermore, a connecting member 42 is attached to the upper end of the cylindrical body 41B, and an eyebolt 49 attached to the tip of a wire 48 is screwed into the connecting member 42.

[0049] 7, the wire 48 is lifted by a crane to lift the pump unit 36 ​​via the protective tube 40. This separates the pump unit 36 ​​from the valve body 18, and closes the foot valve 16. When the connecting portion 41a at the upper end of the second cylindrical body 41 connected to the first cylindrical body 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), and the receiving seat 45 covers the opening 23a of the first seal portion 22. After that, the wire 48 is pulled down by the crane, and the connecting portion 41a of the second cylindrical body 41 is placed 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 and 41 is removed. After that, the wire 48 is again pulled up 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 connecting, lifting, supporting, and separating of the second-highest and subsequent cylinders 41 are repeated until the connecting portion 41a of the lowermost cylinder 41A is exposed. When lifting the second and subsequent cylinders 41, the eyebolt 49 is threaded into the connecting portion 41a of the cylinder 41 located on the receiving seat 45 instead of the connecting member 42, but otherwise the process is the same. During this process, the purging step and the diffusion suppression step are continuously performed. This effectively prevents the vaporized gas in the barrel 15 from leaking and diffusing to the outside 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 Figure 10, the connecting portion 41a of the lower end cylindrical body 41A connected to the pump unit 36 ​​is supported by a receiving seat 45, and the cylindrical body 41 on the receiving seat 45 is separated, and then the extraction process is carried out. In the connecting step shown in Figure 10 of the extraction process, an 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 inert gas to the gas inlet portion 15c and the first seal portion 22 is stopped, and the gas supply source 7 and the piping 8 shown in Figure 1 are disconnected.

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

[0055] On the other hand, when placing the pump unit 36 ​​inside the barrel 15 after maintenance, the procedure is reversed from the procedure 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 with bolts and then lowering them using a crane are repeated. This allows the pump unit 36 ​​to be placed inside the barrel 15 installed in the tank 1, as shown in FIG. 1.

[0056] The submerged pump 10 configured in this manner has the following features.

[0057] The pump section 36 is attached to the lower end of a protective tube 40, which is made up of multiple cylindrical bodies 41 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 in which the protective tube 40 and the pump section 36 are lifted together, a support step in which the upper ends of the cylindrical bodies 41 exposed from the first seal section 22 are held and the pump section 36 is supported via the protective tube 40, and a separation step in which the cylindrical bodies 41 above the first seal section 22 are separated.

[0058] The lifting step, supporting step, and separation step are repeatedly performed while inert gas is sprayed into the opening 23a from the nozzle 26 of the first seal part 22. Therefore, the inert gas sprayed into the opening 23a purifies the inside of the barrel 15 while preventing the vaporized gas from leaking into the atmosphere and diffusing. Thereafter, the spraying of the inert gas from the first seal part 22 is stopped, and an extraction step is performed in which the pump part 36 is extracted together with the first seal part 22 from the upper end of the barrel 15, allowing the pump part 36 to be extracted from the barrel 15, thereby 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, thereby effectively suppressing leakage of vaporized gas from the opening 23a of the first seal portion 22.

[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 ensures that the connecting portion 41a at the upper end of the cylindrical body 41 protruding from the upper end of the barrel 15 is held securely, and the pump unit 36 ​​can be stably suspended via the protective tube 40. Furthermore, the cylindrical body 41 above the receiving seat 45 can be easily and stably separated.

[0061] Receiving seat 45 is composed of divided bodies 46 obtained by dividing an annular body into two or more bodies. Therefore, receiving seat 45 can be easily and reliably arranged so as to surround the outer periphery of cylindrical body 41 of protective tube 40 that is lifted up above 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 it does not include the gas inlet section 15c shown in FIG. 1.

[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 end of the barrel 15 of the second embodiment does not have the upper cover 21 and second seal portion 28 of the first embodiment shown in Figure 1 attached thereto.

[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 base plate 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 allow the pump portion 36 to be inserted therethrough. 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] Similar to the bolt holes 21b of the upper cover 21 shown in Fig. 3, 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. 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 passage 25. The passage 25 is formed by a single through-hole extending in the radial direction of the substrate 23. The nozzle 26 is attached to the radially inner end of the passage 25 and ejects the inert gas in a direction perpendicular to the axis A (radially inward).

[0070] The closing cover 55 is made of a metal plate with the same outer diameter as 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. Bolt holes (not shown) are provided on the outer periphery of the closing cover 55 for bolting it to the flange 15e at the upper end of the barrel 15. The closing cover 55 is placed on the seal portion 22 located 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 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 threading an 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 arranged 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 closing cover 55 is further provided with a lead-out portion 56, a hook portion 57, and a drum 58. The lead-out portion 56 is configured to lead the cable 37 to the outside and protrudes upward from the closing cover 55. The cable 37 led out from the lead-out 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 closing cover 55. The drum 58 is configured to wind the second wire 61 around and hold it, and is provided below the closing cover 55 so as to be located inside the barrel 15.

[0073] The wires serving as the pulling 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 through the insertion hole 55b of the closing cover 55 and is hooked on the hook portion 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 removing 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 lifting step 1 shown in Figure 14, the gas supply source 7 is activated to start supplying 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. The first wire 60 is then connected to a winch 62 and wound up, thereby lifting 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. Also, the eyebolt 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. Thereafter, the exposed second wire 61 is 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 from the closure cover 55, and the parts that protrude from the top 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 pump portion 36 is pulled out from the upper end of the barrel 15 as the winch 62 continues to wind up the second wire 61.

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

[0081] In the submerged pump 10 of the second embodiment configured as described above, the pump section 36 is attached to the lower end of wires 60, 61 for pulling it out from the top end of the barrel 15. Therefore, as in the first embodiment, during maintenance, the pump section 36 can be lifted to the top of the barrel 15 via the wires 60, 61 and pulled out from the top 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 portion 22. Therefore, the inert gas sprayed into the opening 23a prevents the vaporized gas from leaking into the atmosphere from the top end of the barrel 15 and diffusing.

[0082] The present invention is not limited to the configuration of the above embodiment, and various modifications are possible.

[0083] For example, receiving seat 45 may be formed of a single 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 tubular 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 purging step. In the second embodiment, as in the first embodiment, the barrel 15 may be configured 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 required. [Explanation of symbols]

[0087] 1 tank 2 Ceiling wall 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 springs 21 Upper cover 21a opening 21b Bolt hole 21c bolt hole 21d bolt hole 22 First seal part 23 Circuit Board 23a opening 23b Slope 23c Bolt through hole 23d bolt hole 24 Gas supply section 25 Passage 25a Inlet 25b Outlet 26 Nozzle (spout 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 of 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 Insertion hole 46e Seal part 46f Guide groove 46g rib 48 wires 49 Eyebolt 55 Closure cover 55a bolt hole 55b Insertion hole 56 Derivation part 57 Hook 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 the 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; a removal member attached to the pump portion and extending upward within the barrel for removing the pump portion from the upper end of the barrel; a plate-shaped seal portion attached to the upper end of the barrel; Equipped with The sealing portion has an opening through which at least the extraction member can be inserted; a jetting portion that jets an inert gas from a gas supply source into the opening; A submerged pump is provided.

2. 2. The submerged pump according to claim 1, wherein a plurality of said jetting portions are provided.

3. 3. The submerged pump according to claim 2, wherein the plurality of jetting portions are provided at equal intervals around the axis of the barrel.

4. 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.

5. Further, a receiving seat is removably disposed on the sealing portion, the cylindrical body has a connecting portion protruding in a direction intersecting the axis, 5. The submerged pump according to claim 4, 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 pump portion can be supported via the protective tube by holding the connecting portion.

6. 6. The submerged pump according to claim 5, wherein the receiving seat is formed of two or more divided bodies obtained by dividing an annular body in the circumferential direction.

7. 4. The submerged pump according to claim 1, wherein the extraction member is made of a wire that can be wound up by a winding mechanism.

8. A method for extracting a submerged pump that uses a pump unit disposed in a cylindrical barrel that is fixed to a top wall of a tank and extends vertically within the tank to discharge liquefied gas from a discharge unit of the barrel that is disposed above the top wall, comprising: A method for extracting a submerged pump, comprising: lifting the pump unit via an extracting member attached to the pump unit and extending upward within the barrel, while ejecting an inert gas from a gas supply source from an ejection portion into an opening of a seal portion attached to the upper end of the barrel; and extracting the pump unit from the upper end of the barrel.

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