Submerged pump and method for withdrawing a submerged pump

Abstract

This prevents vaporized gases from diffusing into the atmosphere during maintenance. [Solution] The submerged pump 10 comprises a cylindrical barrel 15 fixed to the top wall 2, a protective tube 36 connecting a plurality of cylindrical bodies 37 in a straight tubular shape, a pump unit 32 attached to the lower end of the protective tube 36 and integrally positioned inside the barrel 15 with the protective tube 36, a plate-shaped upper cover 21 attached to the upper end of the barrel 15, and a support seat 40 detachably positioned on the upper cover 21 and supporting the pump unit 32 via the protective tube 36 by holding the connecting portion 37a of the cylindrical body 37. The support seat 40 has an insertion hole 41d that is smaller than the connecting portion 37a of the cylindrical body 37 and through which the portion other than the connecting portion 37a can be inserted.

Description

Technical Field

[0001] The present invention relates to a submerged pump and a method for pulling out a submerged pump.

Background Art

[0002] Patent Document 1 discloses an ammonia tank discharging pump for discharging liquid ammonia in a tank. This pump includes a barrel inserted into the tank, a foot valve provided at the lower end of the barrel, and a discharging pump suspended in the barrel. During maintenance, after closing the foot valve by lifting the discharging pump, the inside of the barrel is purified by supplying purge gas into the barrel and sucking gas from the barrel while supplying purge gas. Then, a head plate that closes the upper end of the barrel is removed, and the discharging pump is pulled out from the upper end of the barrel to suppress the diffusion of ammonia gas to the outside (atmosphere) of the barrel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems 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, since the discharging pump is lifted from the lower part inside the barrel and pulled out from the upper end with the head plate removed, vaporized gas can diffuse from the largely open upper end of the barrel to the outside (atmosphere). In other words, there is room for improvement in the countermeasure against the diffusion of vaporized gas from the inside of the barrel in the pump of Patent Document 1.

[0005] An object of the present invention is to suppress the diffusion of vaporized gas into the atmosphere during maintenance.

Means for Solving the Problems

[0006] One aspect of the present invention provides a submerged pump having a branched discharge section located on the upper side of the top wall of a tank, a cylindrical barrel fixed to the top wall and extending vertically inside the tank with an open upper end, a plurality of cylindrical bodies connected in a straight line and having connecting sections protruding in a direction intersecting the axis of the barrel, a protective tube inserted into the barrel along the axis, a pump section attached to the lower end of the protective tube and integrally positioned inside the barrel with the protective tube, discharging liquefied gas from the discharge section through the space between the barrel and the protective tube, a plate-shaped upper cover attached to the upper end of the barrel and having an opening through which the connecting section can be inserted, and a support seat having an insertion hole smaller than the connecting section of the cylindrical body and through which the portion other than the connecting section can be inserted, detachably positioned on the upper cover so as to cover the opening, and supporting the pump section via the protective tube by holding the connecting section.

[0007] Another aspect of the present invention provides a method for withdrawing a submerged pump, which is fixed to the top wall of a tank and positioned inside a cylindrical barrel extending vertically within the tank, and discharges liquefied gas from a discharge section of the barrel positioned above the top wall through the space between the barrel and the protective tube, using a pump unit attached to the lower end of a protective tube formed by connecting a plurality of cylindrical bodies in a straight line. The method comprises: a lifting step of lifting the protective tube and the pump unit together; a support step of positioning a support seat on the upper cover so as to cover the opening of the upper cover attached to the upper end of the barrel, holding the connecting portion of the upper end of the cylindrical body that protrudes in a direction intersecting the axis of the barrel and is exposed from the upper cover on the support seat, and supporting the pump unit via the protective tube; and a separation step of separating the cylindrical body above the support seat. After repeatedly performing these steps, when the upper end of the cylindrical body at the lower end directly connected to the pump unit is exposed from the upper cover, a withdrawal step is performed to pull out the pump unit together with the upper cover from the upper end of the barrel.

[0008] The pump unit is attached to the lower end of a protective tube, which connects multiple cylindrical bodies in a straight line, and is positioned integrally with this protective tube inside the barrel. A detachable support seat, positioned on the upper cover, supports the pump unit via the protective tube by holding the connecting parts. Therefore, the pump unit can be lifted to the top of the barrel by repeatedly performing a lifting step to hoist the protective tube and pump unit together, a support step to hold the connecting parts of the cylindrical bodies with the support seat and support the pump unit via the protective tube, and a separation step to separate the cylindrical bodies above the support seat. The support seat covering the opening of the upper cover has an insertion hole that is smaller than the connecting parts of the cylindrical bodies and allows the parts other than the connecting parts to be inserted, so in the case of liquefied gases such as ammonia, leakage and diffusion of vaporized gas into the atmosphere can be minimized. Subsequently, by performing an extraction step to pull the pump unit out of the barrel together with the upper cover from the top end of the barrel, the pump unit can be pulled out of the barrel, improving maintainability. [Effects of the Invention]

[0009] This invention makes it possible to suppress the diffusion of vaporized gas into the atmosphere during maintenance. [Brief explanation of the drawing]

[0010] [Figure 1] A cross-sectional view showing a submerged pump according to an embodiment of the present invention attached to a tank. [Figure 2] Enlarged cross-sectional view of section II in Figure 1. [Figure 3] An exploded perspective view of the upper cover at the top end of the barrel and the receiving seat of the first embodiment. [Figure 4] Cross-sectional view of the receiving seat of the first embodiment. [Figure 5] A cross-sectional view showing the shutdown process during maintenance. [Figure 6] A cross-sectional view showing the connecting steps in the lifting process during maintenance. [Figure 7] A cross-sectional view showing the lifting steps in the lifting process during maintenance. [Figure 8] A cross-sectional view showing the support steps during the lifting process for maintenance. [Figure 9] Cross-sectional view showing the separation step of the lifting process during maintenance. [Figure 10] Cross-sectional view showing the connection step of the extraction process during maintenance. [Figure 11] Cross-sectional view showing the extraction step of the extraction process during maintenance. [Figure 12] Cross-sectional view of the receiving seat of the second embodiment. [Figure 13] Cross-sectional view of the receiving seat of the third embodiment. [Figure 14] Cross-sectional view of the receiving seat of the fourth embodiment.

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments 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 the top wall 2 of a tank 1 and discharges a liquefied gas (liquid) such as ammonia from the inside of the tank 1 to a defined external facility.

[0013] The submerged pump 10 includes a barrel 15, a pump section 32, and a protective pipe 36. The pump section 32 is attached to the lower end of the protective pipe 36. The pump section 32 and the protective pipe 36 are integrally inserted into the barrel 15 from above. Further, the submerged pump 10 includes a receiving seat 40 used when pulling out and inserting the pump section 32 with respect to the barrel 15.

[0014] Hereinafter, the configurations of the barrel 15, the pump section 32, the protective pipe 36, and the receiving seat 40 will be specifically described.

[0015] The barrel 15 is cylindrical with open upper and lower ends, passes through the top wall 2, and extends vertically in the tank 1. The barrel 15 has 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 total length of the barrel 15 is formed according to the total height of the tank 1 and is, for example, 50 m. The barrel 15 shown in FIG. 1 is illustrated as a single continuous straight pipe, but in reality, it is composed of a plurality of straight pipes connected in a liquid-tight manner. However, depending on the total height of the tank 1, the barrel 15 may be composed of a single straight pipe. <{0000096}><{0000097}><{0000098}>In the part of the barrel 15 located above the top wall 2, cylindrical liquid discharge part 15b, gas inflow part 15c, and gas outflow part 15d are respectively connected by branching. The liquid discharge part 15b is connected to the delivery pipe 4 connected to the downstream equipment. A shut-off valve 5 is provided in the delivery pipe 4. The gas inflow part 15c is connected to a gas supply source 7 for supplying an inert gas (for example, N2 gas) into the barrel 15. The gas outflow part 15d is connected to equipment (not shown) for treating the inert gas and vaporized gas in the barrel 15. <{0000099}><{0000100}><{0000101}>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. <{0000102}><{0000103}><{0000104}>The foot valve 16 includes a valve seat 17 and a valve body 18. The valve seat 17 is cylindrical and is liquid-tightly attached to the lower end of the barrel 15 by bolting. The valve body 18 is disc-shaped with the same diameter as the flange part at the lower end of the valve seat 17 and is attached so as to be movable in the vertical direction with respect to the valve seat 17. The valve body 18 may have a diameter different from the outer diameter of the flange part of the valve seat 17 or may have a shape other than a disc as long as it can close the valve seat 17 to close the valve. <{0000105}><{0000106}><{0000107}>Each valve body 18 has multiple shaft portions 18a and projection portions 18b spaced apart in the circumferential direction. The shaft portions 18a penetrate the flange portion of the valve seat 17 and project upward. A stopper 19 is attached to the upper end of the shaft portion 18a. Between the stopper 19 and the flange portion, a coil spring 20 is positioned to surround the shaft portion 18a and bias the valve body 18 upward. The projection portions 18b project upward, and a portion of the projection portions 18b is located inside the valve seat 17. When the pump portion 32 is placed on the projection portion 18b, the valve body 18 separates from the valve seat 17 against the biasing force of the coil spring 20 and opens the valve (see Figure 5). When the pump portion 32 separates from the projection portion 18b, the valve body 18 is pressed against the valve seat 17 by the biasing force of the coil spring 20 and closes the valve (see Figure 7).

[0020] Referring to Figures 2 and 3, the upper cover 21 is made of an annular metal plate and is attached to the flange 15e at the upper end of the barrel 15 in a liquid-tight and airtight manner by bolts. The center of the opening 21a of the upper cover 21 is located on axis A. The diameter of the opening 21a is smaller than the outer diameter of the pump section 32 and larger than the outer diameter of the protective tube 36, and is large enough to allow the connecting portion 37a of the protective tube 36, which will be described in detail later, to pass through.

[0021] The outer circumference of the upper cover 21 is provided with a plurality of bolt holes 21b for bolting it to the barrel 15. The inner circumference of the upper cover 21 is provided with a plurality of bolt holes 21c for bolting the sealing member 24. Between the bolt holes 21b and 21c, there is a pair of bolt holes 21d into which an eyebolt 44 (see Figure 10) attached to the lifting wire 43 is screwed. The bolt holes 21c and 21d are non-penetrating, bottomed cylindrical shapes with an open upper end and a closed lower end.

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

[0023] In the normal operation shown in Figures 1 and 2, the guide projections 22 are detached from the upper cover 21. As shown in Figures 3 and 6 through 11, the guide projections 22 are attached to the upper cover 21 when the pump unit 32 is withdrawn from and inserted into the barrel 15. When attached to the upper cover 21, the guide projections 22 protrude upward from the upper cover 21 along axis A. Two guide projections 22 are used for each segment 41, for a total of four. The number of guide projections 22 can be changed as needed, as long as they can guide a pair of segments 41.

[0024] Referring to Figure 2, the sealing member 24 is configured to prevent vaporized gas from inside the barrel 15 from leaking out and diffusing to the outside through the protective tube 36 under normal circumstances. The sealing member 24 comprises a bobbin-shaped base 25 that is liquid-tight and airtightly mounted on the upper cover 21.

[0025] The lower flange portion 25a of the base body 25 is provided with a bolt through-hole corresponding to the bolt hole 21c (see Figure 3) of the upper cover 21. The sealing member 24 is connected to the upper cover 21 by screwing a bolt that has passed through the lower flange portion 25a into the bolt hole 21c of the upper cover 21.

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

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

[0028] The pump unit 32 is submersible and positioned at the lower end of the barrel 15. It discharges liquefied gas that has entered the barrel 15 through the gap between the barrel 15 and the protective tube 36 to the liquid discharge section 15b. By being positioned inside the barrel 15, the pump unit 32 presses the valve body 18 downward, opening the foot valve 16, and is mounted on the valve body 15. The pump unit 32 includes a motor and an impeller (not shown) within its casing. The motor is connected to the terminal block 28 by a cable 33 routed inside the protective tube 36. The cable 33 is composed of multiple wires connected by a connector 34. The cable 33 may also be composed of a single wire without being connected by a connector 34.

[0029] Referring to Figure 1, the protective tube 36 is cylindrical in shape overall and is configured to protect the cable 33. The protective tube 36 is made of metal and is constructed by connecting multiple cylindrical bodies 37 in a straight line, and is inserted along the axis A of the barrel 15. The outer diameter of each cylindrical body 37 is all 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 total length of each cylindrical body 37 is long enough to be lifted by a crane (lifting mechanism) not shown (e.g., 5m). Connectors 34 for the cable 33, as described above, are attached to the upper and lower ends of the cylindrical bodies 37.

[0030] Of the multiple cylindrical bodies 37, the upper and lower ends, excluding the lower cylindrical body 37A and the upper cylindrical body 37B, are each provided with connecting portions 37a that protrude radially outward. The cylindrical body 37A has a connecting portion 37a only at its upper end, and the pump section 32 is connected to the lower end of the cylindrical body 37A. The cylindrical body 37B has a connecting portion 37a only at its lower end. Multiple cylindrical bodies 37 are connected in a straight tubular shape by overlapping the connecting portions 37a of vertically adjacent cylindrical bodies 37 and fastening them with bolts.

[0031] The connecting portion 37a is composed of a flange that protrudes from the cylindrical body 37 in an annular shape. The outer diameter of the connecting portion 37a is smaller than the diameter of the opening 21a of the upper cover 21. As a result, the connecting portion 37a can pass through the opening 21a of the upper cover 21 and be pulled out from the upper end of the barrel 15 to the outside. The connecting portion 37a may be an intermittent annular shape or a shape other than an annular shape, as long as it protrudes radially outward from the cylindrical body 37.

[0032] The upper part of the cylindrical body 37B at the upper end protrudes upward, passing through the upper cover 21 and the sealing member 24. Referring to Figure 6, during maintenance, a connecting member 38 for connecting the wire 43 is attached to the upper end of the cylindrical body 37B. The connecting member 38 is an annular shape with 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 for screwing in the eyebolt 44 of the wire 43.

[0033] Referring to Figures 6 to 8, the support seat 40 is used when pulling out and inserting the pump unit 32 into the barrel 15, and is detachably positioned on the upper cover 21. The support seat 40 is made of metal and supports the pump unit 32 in a suspended position via the protective tube 36 by holding the connecting portion 37a at the upper end of the cylindrical body 37.

[0034] Referring to Figures 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. Each divided body 41 has a base portion 41a, a lower support portion 41b provided at the lower end of the base portion 41a, and an upper support portion 41c provided at the upper end of the base portion 41a, and forms an annular shape when arranged opposite each other with their linear divided edges touching. The receiving seat 40 may be composed of three or more divided bodies 41.

[0035] The base portion 41a is semi-cylindrical in shape, with an inner diameter larger than the outer diameter of the main body portion of the cylindrical body 37 and smaller than the outer diameter of the connecting portion 37a. By arranging a pair of divided bodies 41 facing each other in close proximity, it becomes cylindrical. The internal space of the base portion 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 sealing portion 41e is provided on the inner circumference of the base portion 41a by joining, projecting radially inward toward the protective tube 36. The sealing portion 41e is semi-annular, and becomes an annular shape by arranging a pair of divided bodies 41 facing each other in close proximity. The inner diameter of the sealing portion 41e is larger than the outer diameter of the main body portion of the cylindrical body 37 excluding the connecting portion 37a, but is set to be as small as possible while still allowing the cylindrical body 37 to pass through.

[0037] The lower support portion 41b is joined to the lower end of the base portion 41a. The lower support portion 41b is semi-annular, and becomes an annular shape by arranging a pair of divided bodies 41 facing each other in close proximity. The outer diameter of the lower support portion 41b is larger than the diameter of the opening 21a of the upper cover 21. Also, the outer diameter of the lower support portion 41b is smaller than the dimension between the pair of bolt holes 21d of the upper cover 21, that is, the virtual diameter of the position where the bolt holes 21d are formed in the upper cover 21. As a result, the bolt holes 21d are exposed when the receiving seat 40 is placed on the upper cover 21.

[0038] The lower support portion 41b is provided with a pair of guide grooves 41f extending from the outer circumference toward the dividing edge. The pair of guide grooves 41f extend parallel to each other in a direction perpendicular to the dividing edge. By inserting the guide projection 22 of the upper cover 21 into these guide grooves 41f, the pair of divided bodies 41 can be guided in the direction of approaching each other (radially inward) and the direction of moving away from each other (radially outward). 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 together, 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 semi-annular and becomes an annular shape when a pair of divided bodies 41 are placed facing each other and close together. 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. Multiple 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, we will explain how to remove the pump unit 32 of the submerged pump 10 from the barrel 15 during maintenance.

[0041] The method for withdrawing the submerged pump 10 in this embodiment includes a shut-off step shown in Figure 5, a lifting step shown in Figures 6 to 9, and a withdrawal step shown in Figures 10 and 11.

[0042] In the shutoff process, the gate valve 5 shown in Figure 1 is switched from the open state to the closed state. Also, as shown in Figure 5, the terminal block 28 is removed from the sealing member 24 and the connection of the cable 33 is disconnected.

[0043] Next, in the lifting process, the gas supply source 7 is activated to begin supplying inert gas to the gas inlet 15c. This purifies the inside of the barrel 15 (purge step). In parallel with the purge step, the lifting process also involves repeatedly performing the coupling step shown in Figure 6, the lifting step shown in Figure 7, the support step shown in Figure 8, and the separation step shown in Figure 9 until the coupling portion 37a of the lower end cylindrical body 37A is exposed.

[0044] Specifically, when lifting the uppermost (topmost) cylindrical body 37B, in the connecting step shown in Figure 6, first, the bolt on the lower flange portion 25a of the sealing member 24 is removed to release the connection of the sealing member 24 to the upper cover 21. Next, the sealing member 24 is removed from the cylindrical body 37B. Then, a pair of divided bodies 41 are placed on the upper cover 21 on which the guide projection 22 (see Figure 3) is positioned. In addition, a connecting member 38 is attached to the upper end of the cylindrical body 37B, and the eyebolt 44 attached to the end of the wire 43 is screwed into the connecting member 38.

[0045] Next, in the lifting step shown in Figure 7, the crane lifts the wire 43, thereby lifting the pump unit 32 via the protective tube 36. This separates the pump unit 32 from the valve body 18, and the foot valve 16 closes. When the connecting portion 37a at the upper end of the second cylindrical body 37, which is connected to the first cylindrical body 37B, is exposed above the upper cover 21, or more specifically above the receiving seat 40, the crane stops lifting the wire 43.

[0046] Next, in the support step shown in Figure 8, the pair of divided bodies 41 are moved in the direction toward each other along the guide groove 41f (see Figure 3), and the support seat 40 covers the opening 21a of the upper cover 21. Then, the connecting portion 37a of the second cylindrical body 37 is placed on the support seat 40 by pulling down the wire 43 with a crane. This supports the pump section 32 in a suspended state via the protective tube 36 by the support seat 40.

[0047] Next, in the separation step shown in Figure 9, the bolt connecting the connecting portion 37a of the cylindrical bodies 37B and 37 is removed. Then, 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] Next, the process returns to the connection step shown in Figure 6, and the connection, lifting, support, and separation of the second and subsequent cylindrical bodies 37 from the top are repeatedly performed until the connection portion 37a of the lower cylindrical body 37A is exposed. The only difference when lifting the second and subsequent cylindrical bodies 37 is that an eyebolt 44 is screwed into the connection portion 37a of the cylindrical body 37 located on the receiving seat 40 instead of the connection member 38; otherwise, the process is the same. During this time, the purging step continues.

[0049] In the lifting process, a support seat 40 is positioned on the opening 21a of the upper cover 21 through which the protective tube 36 can be inserted, and the support seat 40 has a through hole 41d through which only the main body portion of the cylindrical body 37 can be inserted. Furthermore, the support seat 40 has a sealing portion 41e that protrudes toward the protective tube 36, creating the smallest possible gap while still allowing the main body portion of the cylindrical body 37 to pass through. Thus, leakage and diffusion of vaporized gas from inside the barrel 15 to the outside can be effectively suppressed.

[0050] As shown in Figure 10, the connecting portion 37a of the lower end cylindrical body 37A connected to the pump section 32 is supported by the support seat 40, and when the cylindrical body 37 on the support seat 40 is separated, the extraction process is performed. In the connecting step of the extraction process shown in Figure 10, an eye bolt 44 is screwed into the bolt hole 21d of the upper cover 21. Also, the bolt connecting the flange 15e of the barrel 15 and the upper cover 21 is removed. In addition, the gas supply source 7 is stopped, and the supply of inert gas to the gas inlet 15c is stopped.

[0051] Next, in the extraction step shown in Figure 11, the wire 43 is pulled up by a crane. This pulls the pump unit 32 out from the upper end of the barrel 15, and the upper cover 21 and the lower cylindrical body 37A are removed together with the pump unit 32.

[0052] On the other hand, when placing the pump unit 32 inside the barrel 15 after maintenance, the work is performed in the reverse order of when the pump unit 32 was removed from the barrel 15. That is, the steps of connecting other cylindrical bodies 37 and 37B to cylindrical bodies 37A and 37 supported by the support seats 40 by bolting them together, and then lowering them with a crane are repeated. As a result, the pump unit 32 can be placed inside the barrel 15 installed in the tank 1, as shown in Figure 1.

[0053] The submerged pump 10 configured in this way has the following characteristics.

[0054] The pump unit 32 is attached to the lower end of a protective tube 36, which connects a plurality of cylindrical bodies 37 in a straight line, and is positioned integrally with the protective tube 36 inside the barrel 15. A support seat 40, which is detachably positioned on the upper cover 21, supports the pump unit 32 via the protective tube 36 by holding the connecting portion 37a. Therefore, the pump unit 32 can be lifted to the top of the barrel 15 by repeatedly performing a lifting step in which the protective tube 36 and the pump unit 32 are lifted together, a support step in which the support seat 40 holds the connecting portion 37a of the cylindrical bodies 37 and supports the pump unit 32 via the protective tube 36, and a separation step in which the cylindrical bodies 37 above the support seat 40 are separated. Furthermore, since the separation step is performed with the pump unit 32 suspended via the protective tube 36 by the support seat 40, the operation of separating the cylindrical bodies 37 above the support seat 40 can be performed easily and stably.

[0055] The receiving seat 40 that covers 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. Therefore, in the case of liquefied gases such as ammonia, leakage and diffusion of vaporized gas into the atmosphere can be minimized. Subsequently, by performing an extraction process to pull out the pump unit 32 together with the upper cover 21 from the upper end of the barrel 15, the pump unit 32 can be pulled out from the barrel 15, thereby improving maintainability.

[0056] The inner circumference of the receiving seat 40 is provided with a sealing portion 41e that protrudes toward the protective tube 36. Therefore, the sealing portion 41e effectively suppresses leakage of vaporized gas from between the inner circumference of the receiving seat 40 and the protective tube 36.

[0057] The support seat 40 is composed of divided parts 41 obtained by dividing an annular body into two or more parts. Therefore, the support seat 40 can be easily and reliably positioned to surround the outer circumference of the cylindrical body 37 of the protective tube 36, which is suspended above the upper cover 21.

[0058] The divided body 41 has a guide groove 41f extending from its outer circumference toward the dividing edge, and the upper cover 21 is provided with a guide projection 22 that is inserted into the guide groove 41f. Therefore, when lifting the connecting portion 37a of the cylindrical body 37, which cannot pass through the insertion hole 41d, to a position above the support seat 40, it can be easily passed by moving the divided body 41 away from it. Furthermore, after lifting the connecting portion 37a, the divided body 41 can be easily returned to the support position by moving the divided body 41 toward it, and the pump section 32 can be reliably supported via the protective tube 36.

[0059] The connecting portion 37a is composed of a flange that protrudes radially outward from the cylindrical body 37. Therefore, the orientation of the receiving seat 40 is eliminated, 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 unless otherwise specified, they will be the same as in the first embodiment. In the drawings referred to below, the same elements as in the first embodiment are denoted by the same reference numerals.

[0061] The sealing portion 41e of the receiving seat 40 may be configured as shown in Figures 12 to 14. In the receiving seat 40 of the second embodiment shown in Figure 12, a plurality of (three in this embodiment) sealing portions 41e 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 Figure 13, a plurality of (three in this embodiment) semi-annular sealing portions 41e are provided at intervals along the axis A of the barrel 15. In the receiving seat 40 of the fourth embodiment shown in Figure 14, the sealing portion 41e is formed in a spiral shape when a pair of divided bodies 41 are placed facing each other and in close proximity. With receiving seats 40 configured in these ways, when the pump unit 32 is withdrawn from the barrel 15, leakage and diffusion of vaporized gas inside the barrel 15 to the outside can be more effectively suppressed.

[0062] Furthermore, the present invention is not limited to the configuration of the above-described embodiment, and various modifications are possible.

[0063] For example, the sealing portion 41e may be separate from the base portion 41a that constitutes the divided body 41, and may be made of a resin with good sliding properties.

[0064] The receiving seat 45 may not be a configuration that divides the annular body in the circumferential direction, but may be composed of a single member. Specifically, the receiving seat 45 may be a configuration in which a groove is provided that forms a C shape when viewed from above, allowing the portion of the cylindrical body 41 other than the connecting portion 41a to be inserted into the annular body which has a cylindrical base portion 46a and annular support portions 46b and 46c, respectively.

[0065] Water (moisture) may be injected as a treatment agent instead of an inert gas into the inlet 15c of the barrel 15. If the sealing portion 41e of the receiving seat 40 can suppress the diffusion of vaporized gas from the barrel 15 to the outside, the barrel 15 may be configured without an inlet 15c and an outlet 15d for supplying an inert gas.

[0066] The liquid discharged by the submerged pump 10 is not limited to liquefied gases such as ammonia, and can be changed as needed. [Explanation of symbols]

[0067] 1 tank 2. Top Wall 4 Delivery pipe 5. Gate valve 7. Gas supply sources 10 Submerged pumps 15 barrels 15a Base Plate 15b Liquid drain 15c Gas inlet 15d Gas outlet 15e flange 16 Foot valve 17 valve seats 18 Valve body 18a Shaft 18b Protrusion 19 Stopper 20 Coil Springs 21 Top cover 21a opening 21b Bolt hole 21c bolt holes 21d Bolt hole 21e Bolt hole 22 Guide protrusion 24 sealing member 25 Base 25a Lower flange section 28 Terminal block 32 Pump section 33 Cables 34 connectors 36 Protection tube 37 Cylinder 37A Bottom cylinder 37B Upper cylindrical body 37a Connecting part 38 Connecting member 40 Receiving seat 41 Split body 41a base 41b Lower support part 41c Upper support part 41d Through hole 41e Seal section 41f Guide groove 41g Rib 43 wires 44 Eyebolts

Claims

1. A cylindrical barrel having a branched discharge section located on the upper side of the top wall of the tank, fixed to the top wall and extending vertically inside the tank, with its upper end open, It is constructed by connecting a plurality of cylindrical bodies in a straight tubular shape, each having a connecting portion that protrudes in a direction intersecting the axis of the barrel, and a protective tube inserted into the barrel along the axis, A pump unit is attached to the lower end of the protective tube and disposed integrally with the protective tube inside the barrel, and discharges liquefied gas from the discharge section through the space between the barrel and the protective tube. A plate-shaped upper cover attached to the upper end of the barrel has an opening through which the connecting portion can be inserted, The cylindrical body has an insertion hole smaller than the connecting portion, through which the portion other than the connecting portion can be inserted, and is detachably positioned on the upper cover so as to cover the opening, and a support seat that supports the pump portion via the protective tube by holding the connecting portion. A submerged pump equipped with [a specific feature].

2. The submerged pump according to claim 1, wherein a sealing portion protruding toward the protective tube is provided on the inner circumference of the receiving seat.

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

4. The divided body has guide grooves that extend from the outer periphery toward the dividing edge. The submerged pump according to claim 3, wherein the upper cover is detachably provided with guide protrusions that are inserted into the guide grooves and guide the two or more divided bodies in an approaching-away direction, where one is moving towards the other and the other away from the other.

5. The submerged pump according to claim 1 or 2, wherein the connecting portion is composed of a flange that protrudes radially outward from the cylindrical body.

6. A method for withdrawing a submerged pump, wherein the pump unit is fixed to the top wall of the tank and positioned inside a cylindrical barrel extending vertically within the tank, and is attached to the lower end of a protective tube formed by connecting multiple cylindrical bodies in a straight line, thereby discharging liquefied gas from the discharge section of the barrel located above the top wall through the space between the barrel and the protective tube, A lifting step for lifting the protective tube and the pump section together, A support step is provided, which is positioned on the upper cover so as to cover the opening of the upper cover attached to the upper end of the barrel, and which holds the upper end connecting portion of the cylindrical body that protrudes in a direction intersecting the axis of the barrel and is exposed from the upper cover on the support step, and which supports the pump section via the protective tube, A separation step to separate the cylindrical body above the aforementioned receiving seat, After repeating this process, A method for extracting a submerged pump, wherein when the upper end of the cylindrical body at the lower end, which is directly connected to the pump section, is exposed from the upper cover, an extraction step is performed to pull out the pump section together with the upper cover from the upper end of the barrel.

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