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 fixed to a top wall 2, a protective tube 36 in which a number of cylindrical bodies 37 are connected in a straight pipe shape, a pump section 32 attached to the lower end of the protective tube 36 and disposed inside the barrel 15 integrally with the protective tube 36, a plate-shaped upper cover 21 attached to the upper end of the barrel 15, and a receiving seat 40 detachably disposed on the upper cover 21 and supporting the pump section 32 via the protective tube 36 by holding a connecting section 37a of the cylindrical bodies 37. The receiving seat 40 has an insertion hole 41d which is smaller than the connecting section 37a of the cylindrical bodies 37 and allows the portion other than the connecting section 37a to be inserted therethrough.

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] The present invention Submerged Pump the tank includes a cylindrical barrel having a branched discharge portion disposed above a top wall of the tank, the barrel being fixed to the top wall and extending in a vertical direction within the tank, the barrel being open at its top end; a plurality of cylinders each having a connecting portion protruding in a direction intersecting an axis of the barrel, connected in a straight tube shape, the protective tube being inserted into the barrel along the axis; a pump portion attached to a lower end of the protective tube and disposed within the barrel integrally with the protective tube, the pump portion discharging liquefied gas from the discharge portion through between the barrel and the protective tube; a plate-shaped upper cover attached to the upper end of the barrel, the upper cover having an opening through which the connecting portion can be inserted; and a receiving seat having an insertion hole that is smaller than the connecting portion and through which a portion of the cylinder other than the connecting portion can be inserted, the receiving seat being detachably disposed on the upper cover so as to cover the opening, and supporting the pump portion via the protective tube by holding the connecting portion. 。 In the first aspect , A seal portion protruding toward the protective tube is provided on the inner periphery of the receiving seat. A submerged pump is provided. In a second aspect, there is provided a submerged pump, wherein the receiving seat is constituted by divided bodies obtained by dividing an annular body into two or more bodies in the circumferential direction.

[0007] Another aspect of the present invention provides a method for extracting a submerged pump, which is disposed in a cylindrical barrel fixed to a top wall of a tank and extending vertically within the tank, and which discharges liquefied gas from a discharge section of the barrel disposed above the top wall through between the barrel and the protective tube by a pump section attached to the lower end of a protective tube formed by connecting a plurality of cylindrical bodies in a straight tube shape, the method including: a lifting step of lifting the protective tube and the pump section together; a support step of placing a receiving seat on the upper cover attached to the upper end of the barrel so as to cover an opening of the upper cover, holding on the receiving seat a connecting section of an upper end of the cylindrical body that protrudes in a direction intersecting the axis of the barrel and is exposed from the upper cover, and supporting the pump section via the protective tube; and a separation step of separating the cylindrical body above the receiving seat. Then, when an upper end of the cylindrical body at the lower end directly connected to the pump section is exposed from the upper cover, an extraction step of extracting the pump section together with the upper cover from the upper end of the barrel is performed.

[0008] The pump unit is attached to the lower end of a protective tube that connects multiple cylindrical bodies in a straight tube shape, and is disposed in the barrel together with the protective tube. A support seat that is detachably disposed on the upper cover supports the pump unit through the protective tube by holding the connecting portion. Therefore, the pump unit can be lifted to the upper part of the barrel by repeatedly performing a lifting step in which the protective tube and the pump unit are lifted together, a support step in which the connecting portion of the cylindrical bodies is held by the support seat and the pump unit is supported through the protective tube, and a separation step in which the cylindrical body above the support seat is separated. The support seat that covers the opening of the upper cover has an insertion hole that is smaller than the connecting portion of the cylindrical body and can insert a portion other than the connecting portion, so that in the case of a liquefied gas such as ammonia, leakage and diffusion of the vaporized gas into the atmosphere can be minimized. Then, a drawing step in which the pump unit is pulled out together with the upper cover from the upper end of the barrel is performed, so that the pump unit can be pulled out from the barrel, improving maintainability. 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 an 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 an upper cover at the upper end of the barrel and a receiving seat of the first embodiment. [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. 11 is a cross-sectional view of a receiving seat according to a second embodiment. [Figure 13] FIG. 11 is a cross-sectional view of a receiving seat according to a third embodiment. [Figure 14] FIG. 13 is a cross-sectional view of a receiving seat according to a fourth embodiment. 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 32, and a protective tube 36. The pump section 32 is attached to the lower end of the protective tube 36. The pump section 32 and the protective tube 36 are inserted together into the barrel 15 from above. The submerged pump 10 also includes a support seat 40 that is used when the pump section 32 is pulled out and inserted into the barrel 15.

[0014] The configurations of the barrel 15, the pump portion 32, the protective tube 36, and the receiving seat 40 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 that is connected to downstream equipment. A gate valve 5 is disposed in the delivery pipe 4. The gas inlet section 15c is used to introduce an inert gas (e.g., N 2 The gas outlet 15d is connected to a facility (not shown) for treating 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 seal member 24 is 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 32 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 32 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 32 and larger than the outer shape of the protective tube 36, and is large enough to allow the connecting section 37a of the protective tube 36, 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 to the seal member 24. A pair of bolt holes 21d is provided between the bolt holes 21b and 21c for screwing in an eye bolt 44 (see FIG. 10) attached to a lifting wire 43. The bolt holes 21c and 21d are each a non-through, bottomed cylinder with an open upper end and a closed lower end.

[0022] A guide protrusion 22 is provided between the opening 21a and the bolt hole 21c of the upper cover 21. The guide protrusion 22 is configured to guide a pair of divided bodies 41 that constitute the receiving seat 40. The guide protrusion 22 is configured by a stud bolt, and is detachably screwed into a bottomed cylindrical bolt hole 21e provided in the upper cover 21.

[0023] 1 and 2, the guide protrusions 22 are normally removed from the upper cover 21. As shown in FIGS. 3 and 6 to 11, when the pump section 32 is pulled out from or inserted into the barrel 15, the guide protrusions 22 are attached to the upper cover 21. When attached to the upper cover 21, the guide protrusions 22 protrude upward from the upper cover 21 along the axis A. Two guide protrusions 22 are used for each divided body 41, for a total of four guide protrusions 22. The number of guide protrusions 22 can be changed as necessary as long as it is within a range in which the pair of divided bodies 41 can be guided.

[0024] 2, sealing member 24 is configured to normally prevent vaporized gas in barrel 15 from leaking and diffusing to the outside through protective tube 36. Seal member 24 includes a bobbin-shaped base body 25 that is attached to upper cover 21 in a liquid-tight and airtight manner.

[0025] The lower flange portion 25a of the base body 25 is provided with bolt through holes corresponding to the bolt holes 21c (see FIG. 3) of the upper cover 21. The seal member 24 is connected to the upper cover 21 by screwing the bolts that pass through the lower flange portion 25a into the bolt holes 21c of the upper cover 21.

[0026] The upper flange of the base 25 is provided with bolt through holes for bolting the terminal block 28. A gland packing (not shown) for sealing with the protective tube 36 is attached to the inner periphery between the lower flange 25a and the upper flange.

[0027] 1, a terminal block 28 is attached by bolts to the upper side of the seal member 24. A power supply connection portion for supplying power to the pump unit 32 and a control panel for controlling the pump unit 32 are connected to the terminal block 28.

[0028] The pump unit 32 is of an immersion type and is disposed at the lower end of the barrel 15. The pump unit 32 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 36. When the pump unit 32 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 32 includes a motor and an impeller (not shown) in a casing. The motor is connected to the terminal block 28 by a cable 33 arranged in the protective tube 36. The cable 33 is configured by connecting a plurality of electric wires by a connector 34. The cable 33 may be configured by a single electric wire without being connected by the connector 34.

[0029] 1, the protective tube 36 is cylindrical as a whole and is configured to protect the cable 33. The protective tube 36 is made of metal and configured by connecting a plurality of cylindrical bodies 37 in a straight tube shape, and is inserted along the axis A of the barrel 15. The outer diameter of each cylindrical body 37 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. The entire length of each cylindrical body 37 is a length (e.g., 5 m) that allows it to be hoisted by a crane (hoisting mechanism) not shown. The connectors 34 of the cable 33 described above are attached to the upper and lower ends of the cylindrical bodies 37.

[0030] A connecting portion 37a protruding radially outward is provided at each of the upper and lower ends of the multiple cylindrical bodies 37 except for the lower cylindrical body 37A and the upper cylindrical body 37B. The connecting portion 37a is provided only at the upper end of the cylindrical body 37A, and the pump portion 32 is connected to the lower end of the cylindrical body 37A. The connecting portion 37a is provided only at the lower end of the cylindrical body 37B. The multiple cylindrical bodies 37 are connected in a straight pipe shape by overlapping the connecting portions 37a of the vertically adjacent cylindrical bodies 37 and fastening them with bolts.

[0031] The connecting portion 37a is configured by a flange that protrudes in a circular ring shape relative to the cylindrical body 37. The outer diameter of the connecting portion 37a is smaller than the diameter of the opening 21a of the upper cover 21. This allows the connecting portion 37a to pass through the opening 21a of the upper cover 21 and be removable from the upper end of the barrel 15 to the outside. As long as the connecting portion 37a is configured to protrude radially outward relative to the cylindrical body 37, it may be an interrupted circular ring shape or may have a shape other than a ring.

[0032] An upper portion of the upper end cylinder 37B protrudes upward through the upper cover 21 and the seal member 24. Referring to Fig. 6, during maintenance, a connecting member 38 for connecting the wire 43 is attached to the upper end of the cylinder 37B. The connecting member 38 is annular and has an outer diameter larger than the diameter of the opening 21a of the upper cover 21. The connecting member 38 is provided with a bolt hole into which the eyebolt 44 of the wire 43 is screwed.

[0033] 6 to 8, receiving seat 40 is used when pump section 32 is pulled out from and inserted into barrel 15, and is detachably disposed on upper cover 21. Receiving seat 40 is made of metal, and supports pump section 32 in a suspended position via protective tube 36 by holding connecting section 37a at the upper end of cylindrical body 37.

[0034] 2 to 4, the receiving seat 40 of the first embodiment is composed of a pair of divided bodies 41 obtained by dividing a bobbin-shaped annular body into two in the circumferential direction as a whole. Each divided body 41 includes a base 41a, a lower support portion 41b provided at the lower end of the base 41a, and an upper support portion 41c provided at the upper end of the base 41a, 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 40 may be composed of three or more divided bodies 41.

[0035] The base 41a is semi-cylindrical with an inner diameter larger than the outer diameter of the main body of the cylindrical body 37 and smaller than the outer diameter of the connecting portion 37a, and is cylindrical in shape when the pair of divided bodies 41 are disposed close to each other in opposition to each other. The internal space of the base 41a forms an insertion hole 41d through which the portion of the cylindrical body 37 other than the connecting portion 37a can be inserted.

[0036] A seal portion 41e is provided by joining on the inner periphery of the base portion 41a, protruding radially inward toward the protective tube 36. The seal portion 41e is semicircular, and is formed by arranging the pair of divided bodies 41 facing each other and close to each other. The inner diameter of the seal portion 41e is larger than the outer diameter of the main body of the cylindrical body 37 excluding the connecting portion 37a, but is set as small as possible within the range in which the cylindrical body 37 can be inserted.

[0037] The lower support portion 41b is joined to the lower end of the base portion 41a. The lower support portion 41b has a semicircular ring shape, which is formed by arranging the pair of divided bodies 41 facing each other and close to each other. The outer diameter of the lower support portion 41b is larger than the diameter of the opening 21a of the upper cover 21. The outer diameter of the lower support portion 41b is also smaller than the dimension between the pair of bolt holes 21d of the upper cover 21, that is, the imaginary diameter at the position where the bolt holes 21d are formed in the upper cover 21. As a result, the bolt holes 21d are set to be exposed when the receiving seat 40 is arranged on the upper cover 21.

[0038] The lower support portion 41b is provided with a pair of guide grooves 41f extending from the outer periphery toward the dividing edge. The pair of guide grooves 41f extend parallel to the dividing edge in a direction perpendicular to the dividing edge. By inserting the guide protrusions 22 of the upper cover 21 into these guide grooves 41f, the pair of divided bodies 41 can be guided in a direction in which they approach each other (inward in the radial direction) and move away from each other (outward in the radial direction). When the pair of divided bodies 41 are separated, the connecting portion 37a of the protective tube 36 can be inserted into the insertion hole 41d. When the pair of divided bodies 41 are close to each other, the connecting portion 37a of the protective tube 36 cannot be inserted into the insertion hole 41d.

[0039] The upper support portion 41c is joined to the upper end of the base portion 41a. The upper support portion 41c is semicircular, and is formed by arranging the pair of divided bodies 41 facing each other and close to each other. The outer diameter of the upper support portion 41c is larger than the outer diameter of the connecting portion 37a of the cylindrical body 37 and smaller than the outer diameter of the lower support portion 41b. The outer diameter of the upper support portion 41c is large enough to expose the guide groove 41f. A plurality of reinforcing ribs 41g are provided between the upper support portion 41c and the lower support portion 41b at intervals in the circumferential direction. The ribs 41g are joined to the base portion 41a, the lower support portion 41b, and the upper support portion 41c, respectively.

[0040] Next, a method for pulling out the pump portion 32 of the submerged pump 10 from the barrel 15 during maintenance will be described.

[0041] 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.

[0042] In the shutoff step, 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 28 is removed from the seal member 24, and the connection of the cable 33 is released.

[0043] Next, in the lifting step, the gas supply source 7 is operated to start supplying the inert gas to the gas inlet 15c. This purifies the inside of the barrel 15 (purging step). In the lifting step, in parallel with the purging 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 part 37a of the lower end cylinder 37A is exposed.

[0044] Specifically, when lifting the upper end (first from the top) cylinder 37B, in the connecting step shown in Fig. 6, first, the bolts of the lower flange portion 25a of the seal member 24 are removed, and the connection of the seal member 24 to the upper cover 21 is released. Next, the seal member 24 is removed from the cylinder 37B. After that, a pair of divided bodies 41 are placed on the upper cover 21 on which the guide protrusions 22 (see Fig. 3) are arranged. In addition, a connecting member 38 is attached to the upper end of the cylinder 37B, and an eyebolt 44 attached to the tip of a wire 43 is screwed into the connecting member 38.

[0045] 7, the wire 43 is pulled up by a crane to hoist the pump unit 32 via the protective tube 36. This separates the pump unit 32 from the valve body 18 and closes the foot valve 16. When the connecting portion 37a at the upper end of the second cylinder 37 connected to the first cylinder 37B is exposed above the upper cover 21, more specifically above the receiving seat 40, the lifting of the wire 43 by the crane is stopped.

[0046] 8, the pair of divided bodies 41 are moved toward each other along the guide grooves 41f (see FIG. 3) to cover the opening 21a of the upper cover 21 with the receiving seat 40. Then, the wire 43 is pulled down by the crane to place the connecting portion 37a of the second cylindrical body 37 on the receiving seat 40. As a result, the pump portion 32 is supported in a suspended state by the receiving seat 40 via the protective tube 36.

[0047] 9, the bolt connecting the connecting portion 37a of the cylindrical bodies 37B and 37 is removed. After that, the wire 43 is pulled up again by the crane, and the connection of the cable 33 by the connector 34 is released. This separates the cylindrical body 37B above the receiving seat 40.

[0048] 6, the second and subsequent cylinders 37 are repeatedly connected, lifted, supported, and separated until the connecting portion 37a of the lowermost cylinder 37A is exposed. When lifting the second and subsequent cylinders 37, the eyebolt 44 is screwed into the connecting portion 37a of the cylinder 37 located on the receiving seat 40 instead of the connecting member 38, but the other points are the same. During this time, the purging step continues.

[0049] Here, in the lifting process, a receiving seat 40 having an insertion hole 41d through which only the main body of the cylindrical body 37 can be inserted is disposed on the opening 21a of the upper cover 21 through which the protective tube 36 can be inserted. Moreover, the receiving seat 40 is formed with a seal portion 41e protruding toward the protective tube 36 so as to make the gap as small as possible within the range in which the main body of the cylindrical body 37 can be inserted. This effectively prevents the vaporized gas in the barrel 15 from leaking to the outside and diffusing.

[0050] As shown in Fig. 10, the connecting portion 37a of the lower end cylinder 37A connected to the pump portion 32 is supported by the receiving seat 40, and the cylinder 37 on the receiving seat 40 is separated, and then the extraction process is performed. In the connection step shown in Fig. 10 of the extraction process, the eyebolt 44 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, and the supply of the inert gas to the gas inlet portion 15c is stopped.

[0051] 11, wire 43 is pulled up by a crane. As a result, pump portion 32 is pulled out from the upper end of barrel 15, and upper cover 21 and lower cylinder body 37A are removed together with pump portion 32.

[0052] On the other hand, when placing the pump unit 32 in the barrel 15 after maintenance, the procedure is reversed from that for removing the pump unit 32 from the barrel 15. That is, the steps of connecting the other cylindrical bodies 37, 37B to the cylindrical bodies 37A, 37 supported by the receiving seat 40 by bolting, and then pulling them down by a crane are repeated. This allows the pump unit 32 to be placed in the barrel 15 installed in the tank 1, as shown in FIG. 1.

[0053] The submerged pump 10 thus configured has the following features.

[0054] The pump section 32 is attached to the lower end of a protective tube 36 in which a plurality of cylindrical bodies 37 are connected in a straight pipe shape, and is disposed in the barrel 15 together with the protective tube 36. The receiving seat 40, which is detachably disposed on the upper cover 21, supports the pump section 32 via the protective tube 36 by holding the connecting portion 37a. Therefore, the pump section 32 can be lifted to the upper part of the barrel 15 by repeatedly performing a lifting step in which the protective tube 36 and the pump section 32 are lifted together, a supporting step in which the receiving seat 40 holds the connecting portion 37a of the cylindrical bodies 37 and supports the pump section 32 via the protective tube 36, and a separating step in which the cylindrical bodies 37 above the receiving seat 40 are separated. The separating step is performed in a state in which the pump section 32 is suspended by the receiving seat 40 via the protective tube 36, so that the operation of separating the cylindrical bodies 37 above the receiving seat 40 can be easily and stably performed.

[0055] Since the receiving seat 40 covering the opening 21a of the upper cover 21 has an insertion hole 41d that is smaller than the connecting portion 37a of the cylindrical body 37 and allows the portion other than the connecting portion 37a to be inserted therethrough, in the case of a liquefied gas such as ammonia, leakage and diffusion of the vaporized gas into the atmosphere can be minimized. Then, by performing a withdrawal process in which the pump portion 32 is withdrawn together with the upper cover 21 from the upper end of the barrel 15, the pump portion 32 can be withdrawn from the barrel 15, thereby improving maintainability.

[0056] A seal portion 41e protruding toward the protective tube 36 is provided on the inner periphery of the receiving seat 40. Therefore, the seal portion 41e can effectively prevent the vaporized gas from leaking out from between the inner periphery of the receiving seat 40 and the protective tube 36.

[0057] The receiving seat 40 is composed of divided bodies 41 obtained by dividing an annular body into two or more bodies. Therefore, the receiving seat 40 can be easily and reliably arranged so as to surround the outer periphery of the cylindrical body 37 of the protective tube 36 that is lifted up above the upper cover 21.

[0058] A guide groove 41f extending from the outer periphery toward the divided edge is formed in the divided body 41, and a guide protrusion 22 to be inserted into the guide groove 41f is provided in the upper cover 21. Therefore, when the connecting portion 37a of the cylindrical body 37, which cannot pass through the insertion hole 41d, is lifted above the receiving seat 40, the divided body 41 can easily pass through by moving in a direction away from the receiving seat 40. In addition, after the connecting portion 37a is lifted, the divided body 41 can easily return to the support position by moving in a direction toward the receiving seat 40, and the pump portion 32 can be reliably supported via the protective tube 36.

[0059] The connecting portion 37a is configured by a flange that protrudes radially outward from the cylindrical body 37. Therefore, there is no need to specify a direction when arranging the receiving seat 40, and the connecting portion 37a can be easily and stably held by the receiving seat 40.

[0060] 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.

[0061] The seal portion 41e of the receiving seat 40 may be configured as shown in Fig. 12 to Fig. 14. In the receiving seat 40 of the second embodiment shown in Fig. 12, a plurality of seal portions 41e (three in this embodiment) are provided at intervals along the axis A of the barrel 15 (axis of the protective tube 36). In the receiving seat 40 of the third embodiment shown in Fig. 13, a plurality of seal portions 41e (three in this embodiment) in a semicircular ring shape are provided at intervals along the axis A of the barrel 15. In the receiving seat 40 of the fourth embodiment shown in Fig. 14, the seal portion 41e is formed in a spiral shape when the pair of divided bodies 41 are arranged in close proximity to each other in an opposed manner. In the receiving seat 40 configured in this way, when the pump portion 32 is pulled out of the barrel 15, the vaporized gas in the barrel 15 can be more effectively prevented from leaking and diffusing to the outside.

[0062] The present invention is not limited to the configurations of the above-described embodiments, and various modifications are possible.

[0063] For example, the seal portion 41e may be a separate body from the base portion 41a constituting the divided body 41, and may be made of a resin having good sliding properties.

[0064] Receiving seat 45 may be configured as one member, instead of dividing an annular body in the circumferential direction. Specifically, receiving seat 45 may be configured to have a groove 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.

[0065] Water (moisture) may be sprayed as a treatment agent instead of an inert gas into inlet portion 15c of barrel 15. If seal portion 41e of receiving seat 40 can suppress the diffusion of vaporized gas in barrel 15 to the outside, barrel 15 may not be provided with inlet portion 15c and outlet portion 15d for supplying an inert gas.

[0066] 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]

[0067] 1 Tank 2. Ceiling 4 Delivery pipe 5. Gate valve 7 Gas supply source 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 21e Bolt hole 22 Guide protrusion 24 Sealing material 25 Base 25a Lower flange 28 Terminal block 32 Pump section 33 Cable 34 Connector 36 Protection tube 37 Cylinder 37A Bottom cylinder 37B Upper end of cylinder 37a Connecting part 38 Connecting members 40 Receiving seat 41 Split body 41a base 41b Lower support part 41c Upper support part 41d Through hole 41e Seal part 41f Guide groove 41g Rib 43 Wire 44 Eyebolt

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 protective tube formed by connecting a plurality of cylindrical bodies in a straight tube shape, each having a connecting portion protruding in a direction intersecting with an axis of the barrel, and the protective tube being inserted into the barrel along the axis; a pump section attached to a lower end of the protective tube and disposed in the barrel integrally with the protective tube, the pump section discharging the liquefied gas from the discharge section through a gap between the barrel and the protective tube; a plate-shaped upper cover attached to an upper end of the barrel, the upper cover having an opening through which the connecting portion can be inserted; a receiving seat having an insertion hole which is smaller than the connecting portion of the cylindrical body and through which a portion other than the connecting portion can be inserted, the receiving seat being detachably disposed on the upper cover so as to cover the opening, and supporting the pump portion via the protective tube by holding the connecting portion; Equipped with A submerged pump, wherein an inner periphery of the receiving seat is provided with a seal portion protruding toward the protective pipe.

2. 2. The submerged pump according to claim 1, wherein the receiving seat is constituted by two or more divided bodies obtained by dividing an annular body in the circumferential direction.

3. A cylindrical barrel having a branched discharge portion disposed above a top wall of the tank, fixed to the top wall, extending vertically within the tank, and having an open upper end; a protective tube formed by connecting a plurality of cylindrical bodies in a straight tube shape, each having a connecting portion protruding in a direction intersecting with an axis of the barrel, and the protective tube being inserted into the barrel along the axis; a pump section attached to a lower end of the protective tube and disposed in the barrel integrally with the protective tube, the pump section discharging the liquefied gas from the discharge section through a gap between the barrel and the protective tube; a plate-shaped upper cover attached to an upper end of the barrel, the upper cover having an opening through which the connecting portion can be inserted; a receiving seat having an insertion hole which is smaller than the connecting portion of the cylindrical body and through which a portion other than the connecting portion can be inserted, the receiving seat being detachably disposed on the upper cover so as to cover the opening, and supporting the pump portion via the protective tube by holding the connecting portion; Equipped with The receiving seat is constituted by two or more divided bodies obtained by dividing an annular body in the circumferential direction.

4. The divided body has a guide groove formed therein, the guide groove extending from an outer periphery toward a divided edge, 4. The submerged pump according to claim 2 or 3, wherein the upper cover is provided with a detachable guide protrusion that is inserted into the guide groove and guides the two or more divided bodies in a contact direction, that is, a direction in which the two or more divided bodies approach each other and a direction in which the two or more divided bodies move away from each other.

5. 4. The submerged pump according to claim 1, wherein the connecting portion is configured by a flange protruding radially outward from the cylindrical body.

6. A method for extracting a submerged pump, which is disposed in a cylindrical barrel fixed to a top wall of a tank and extending vertically within the tank, and which discharges liquefied gas from a discharge portion of the barrel disposed above the top wall through a gap between the barrel and the protective tube by a pump portion attached to a lower end of a protective tube formed by connecting a plurality of cylindrical bodies in a straight tube shape, comprising: a lifting step for lifting the protective pipe and the pump unit together; a support step of placing a receiving seat on the upper cover attached to the upper end of the barrel so as to cover an opening of the upper cover, holding a connecting portion of the upper end of the cylindrical body, which protrudes in a direction intersecting with the axis of the barrel and is exposed from the upper cover, on the receiving seat, and supporting the pump unit via the protective tube; a separation step of separating the cylindrical body above the receiving seat; After repeating the above steps, When the upper end of the cylindrical body whose lower end is directly connected to the pump section is exposed from the upper cover, an extraction process is performed to extract the pump section together with the upper cover from the upper end of the barrel.

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