Submerged pump

Abstract

To provide a submerged pump capable of removing liquefied gas remaining in the motor chamber. [Solution] The submerged pump 1 according to the present invention has a housing 2 housed in a pump column T1 and housing a rotating shaft 5 and an impeller 7. The housing has a motor chamber R2, a pump chamber R1, a recess 2h located in the motor chamber, first passages 2g, 62, 8 communicating with the motor chamber and the pump chamber, second passages 2e, 30, 31 communicating with the upper space R21 and the first internal space Sc1, and a third passage 2f communicating with the recess and the second passage. The second passage comprises a vertically movable lifting passage and a housing passage that vertically accommodates a part of the lifting passage. The third passage comprises a first opening 2f1 opening into the recess and a second opening 2f2 opening into the housing passage. When the second internal space is partitioned, the lifting passage closes the second opening. When the submerged pump is lifted, the lifting passage communicates with the third passage.

Description

Technical Field

[0001] The present invention relates to a submerged pump.

Background Art

[0002] A submerged pump is used to extract liquefied gas (e.g., liquefied natural gas, etc.) from a storage tank in which the liquefied gas is stored (see, for example, Patent Document 1). The submerged pump is immersed in the liquefied gas stored in the storage tank. The submerged pump includes a pump chamber in which an impeller is accommodated and a motor chamber in which a motor is accommodated. The impeller sucks and discharges the handling liquid from a suction port disposed at the lower end of the pump chamber. A part of the handling liquid discharged from the impeller is used for lubrication and cooling of the bearing and is introduced into the motor chamber through an introduction path (e.g., a bearing, etc.) and is also used for cooling the motor.

[0003] The submerged pump is taken out of the storage tank, for example, for maintenance. When the operation of the submerged pump stops, the inside of the submerged pump is filled with the remaining liquefied gas. When the submerged pump is pulled upward above the liquid level, the liquefied gas remaining in the pump chamber is discharged from the suction port, and the liquefied gas remaining in the motor chamber passes through the introduction path and the pump chamber and is discharged from the suction port.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] It should be noted that there seems to be a formatting error in the original text where the tag for "

特許文献

先行技術文献

Patent Documents

[0006] The present invention aims to provide a submerged pump capable of removing liquefied gas remaining in the motor chamber. [Means for solving the problem]

[0007] A submerged pump in one embodiment of the present invention is a submerged pump housed in a cylindrical pump column and immersed in a fluid being handled, comprising: a motor; a rotating shaft attached to the motor; an impeller attached to the rotating shaft; and a housing housing the rotating shaft and the impeller, wherein the housing has a contact portion that abuts against the pump column and divides the internal space of the pump column into a first internal space and a second internal space located above the first internal space; a motor chamber housing the motor; a pump chamber located below the motor chamber housing the impeller; a recess located in the motor chamber and concave downwards; a first flow path located below the motor and communicating with the motor chamber and the pump chamber; and at least one second flow path within the pump chamber that communicates with an upper space located above the motor and the first internal space. The first internal space is capable of receiving the handling fluid drawn into the submerged pump, and the second internal space is capable of receiving the handling fluid discharged from the submerged pump. The second internal space comprises a lifting passage that can move up and down between an upward position and a downward position, and a housing passage that can move up and down a part of the lifting passage. The third internal space comprises a first opening that opens to the lowest part of the inner surface of the recess, and a second opening that opens to the housing passage. When the contact portion separates the first internal space and the second internal space, the lifting passage is positioned in the upward position and closes the second opening. When the submerged pump is pulled up and the contact portion does not separate the first internal space and the second internal space, the lifting passage is positioned in the downward position and communicates with the third internal space. [Effects of the Invention]

[0008] The present invention provides a submerged pump capable of removing liquefied gas remaining in the motor chamber. [Brief explanation of the drawing]

[0009] [Figure 1]This is a schematic cross-sectional view showing the usage state of the submerged pump according to the present invention. [Figure 2] This is a cross-sectional view of the submerged pump shown above. [Figure 3] This is a partially enlarged cross-sectional view showing part A in Figure 2. [Figure 4] This is a schematic diagram showing the flow of the liquid being handled when the submerged pump is discharging it. [Figure 5] This is a partially enlarged cross-sectional view showing part A in Figure 2 when the submerged pump described above is lifted up. [Figure 6] This is a schematic diagram showing the flow of the fluid being handled when the submerged pump is lifted. [Modes for carrying out the invention]

[0010] Embodiments of the submerged pump according to the present invention (hereinafter referred to as "the pump") are described below. In the following description, the drawings will be referenced as appropriate. In each drawing, the same reference numerals are used for the same members and elements, and redundant explanations are omitted. In addition, the dimensional ratios of each element may be exaggerated for the sake of explanation and are not limited to the ratios shown in each drawing.

[0011] ●Submerged pump● ● Submerged pump configuration Figure 1 is a schematic cross-sectional view showing the operating state of this pump.

[0012] The pump 1 is located inside a storage tank T in which the handling liquid is stored, and it transports the handling liquid to the outside of the storage tank T. The pump 1 is housed in a pump column T1. The pump 1 is immersed in the handling liquid within the pump column T1. The pump 1 is an example of a submerged pump according to the present invention.

[0013] "Handling liquid" refers to the liquid handled (transported) by this pump 1. Examples of handling liquids include liquefied gases such as liquefied natural gas and liquefied ammonia.

[0014] The shape of the pump column T1 is cylindrical. The pump column T1 is disposed through the ceiling Ta of the storage tank T and extends into the handling liquid from the ceiling Ta. The pump column T1 includes a contact surface T1a and a protrusion T1b.

[0015] The inner peripheral surface of the lower part of the pump column T1 continuously expands (is inclined) downward to form the contact surface T1a. The contact surface T1a is disposed at the lower part of the pump column T1.

[0016] In the vertical direction, the part of the inner peripheral surface of the pump column T1 located below the contact surface T1a protrudes inward of the pump column T1 to form the protrusion T1b.

[0017] A liquid feed path T2 for the handling liquid is connected to the upper outer peripheral surface of the pump column T1. The upper end of the pump column T1 is liquid-tightly sealed by a head plate T3. The lower end of the pump column T1 is opened and closed by a foot valve T4.

[0018] A lift shaft T5 is disposed through the head plate T3. The main pump 1 and the lift shaft T5 are connected to a support cable T6. The main pump 1 is moved up and down within the pump column T1 according to the lifting and lowering of the lift shaft T5.

[0019] When the pump 1 is housed in the pump column T1, the pump 1 abuts against the abutting surface T1a and is supported by the abutting surface T1a. The foot valve T4 is pushed downward by the pump 1 and is open. At this time, the internal space Sc of the pump column T1 is partitioned into a space below the position where the pump 1 and the abutting surface T1a abut (hereinafter referred to as "first internal space Sc1") and a space above the same position (hereinafter referred to as "second internal space Sc2"). That is, the second internal space Sc2 is arranged above the first internal space Sc1. Also, a space (hereinafter referred to as "inflow space Sin") through which the handling liquid sucked by the pump 1 flows is formed between the pump column T1 and the foot valve T4. The first internal space Sc1 communicates with the inflow space Sin. Therefore, a part of the handling liquid flowing into the inflow space Sin also flows into the first internal space Sc1.

[0020] When the pump 1 is lifted to the pump lift position due to maintenance or the like, the pump 1 is separated from the abutting surface T1a, and the foot valve T4 is closed.

[0021] Figure 2 is a cross-sectional view of the pump 1. In the following description, Figure 1 is appropriately referred to together with Figure 2.

[0022] The pump 1 includes a housing 2, a motor 4, a rotating shaft 5, a bearing 6, an impeller 7, and a thrust balance mechanism 8.

[0023] In the following description, the "radial direction" is the radial direction of the rotating shaft 5. The "circumferential direction" is the circumferential direction of the rotating shaft 5.

[0024] The housing 2 houses the motor 4, the rotating shaft 5, the bearing 6, the impeller 7, and the thrust balance mechanism 8. The shape of the housing 2 is a substantially cylindrical shape along the vertical direction. The housing 2 includes a peripheral wall portion 2a, an upper wall portion 2b, a partition wall portion 2c, a lower wall portion 2d, two insertion holes 2e (one not shown), two drain holes 2f (one not shown), a bearing bracket 2g, a recess 2h, a pump chamber R1, a motor chamber R2, and two lead-out members 3 (one not shown).

[0025] In the following explanation, "upstream side" refers to the upstream side of the flow of the handling fluid inside the enclosure 2, and "downstream side" refers to the downstream side of the flow of the handling fluid inside the enclosure 2.

[0026] The peripheral wall portion 2a is a roughly cylindrical wall that partitions the motor room R2.

[0027] The upper wall portion 2b is a wall positioned above the peripheral wall portion 2a. The upper wall portion 2b partitions the motor chamber R2 and is positioned above the motor 4. The upper wall portion 2b is equipped with a bearing bracket 2b1. A portion of the upper wall portion 2b protrudes downward in a cylindrical shape, forming the bearing bracket 2b1. The bearing bracket 2b1 holds the bearing 61 (described later).

[0028] The partition wall 2c is located below the peripheral wall 2a and is positioned between the pump chamber R1 and the motor chamber R2. The partition wall 2c separates the pump chamber R1 and the motor chamber R2. The partition wall 2c is positioned below the motor 4. The partition wall 2c comprises an upper surface 2c1, a retaining hole 2c2, and a discharge port 2c3. The retaining hole 2c2 is located in the center of the partition wall 2c and is a through-hole that penetrates the partition wall 2c in the vertical direction. The discharge port 2c3 is a through-hole that penetrates the partition wall 2c in an oblique upward direction. The discharge port 2c3 communicates with the pump chamber R1 and the external space of the pump 1 (the internal space Sc of the pump column T1).

[0029] The lower wall portion 2d is a wall located below the partition wall portion 2c. The lower wall portion 2d partitions the pump chamber R1. The lower wall portion 2d comprises a first flange portion 2d1, a second flange portion 2d2, and a suction port 2d3. The upper end of the lower wall portion 2d protrudes radially outward, forming the first flange portion 2d1. In the vertical direction, the central portion of the lower wall portion 2d protrudes radially outward, forming the second flange portion 2d2. The lower part of the lower wall portion 2d is reduced in diameter, forming the suction port 2d3. That is, the suction port 2d3 is located at the lower end of the housing 2. The second flange portion 2d2 is an example of a contact portion in the present invention.

[0030] The through-hole 2e is a through-hole that penetrates vertically through the peripheral wall portion 2a, the partition wall portion 2c, and the lower wall portion 2d (first flange portion 2d1, second flange portion 2d2). The through-hole 2e comprises a first through-hole 2e1, a second through-hole 2e2, and a third through-hole 2e3. The first through-hole 2e1 is located at the upper part of the peripheral wall portion 2a. The second through-hole 2e2 is located at the lower part of the peripheral wall portion 2a, the partition wall portion 2c, and the first flange portion 2d1. The third through-hole 2e3 is located at the second flange portion 2d2. The second through-hole 2e2 is an example of a dwelling flow path in the present invention.

[0031] The drain hole 2f is a flow path for discharging the handling fluid remaining in the recess 2h. The drain hole 2f opens to the upper surface 2c1 of the partition wall 2c (the bottom surface 2h1 of the recess 2h (described later)) and to the second insertion hole 2e2. That is, the drain hole 2f is located in the partition wall 2c and communicates with the recess 2h (motor chamber R2) and the second insertion hole 2e2. In a radial view, the shape of the drain hole 2f is approximately "L-shaped". The drain hole 2f has a first opening 2f1 and a second opening 2f2. The first opening 2f1 opens to the bottom surface 2h1, and the second opening 2f2 opens to the second insertion hole 2e2. The drain hole 2f is an example of a third flow path in the present invention.

[0032] The bearing bracket 2g holds the bearing 62 (described later). The bearing bracket 2g has a two-stage cylindrical shape. The inner diameter of the upper part of the bearing bracket 2g is smaller than the inner diameter of the lower part of the bearing bracket 2g. The bearing bracket 2g is held in the partition wall 2c (holding hole 2c2). The bearing bracket 2g is positioned below the motor 4. The upper part of the bearing bracket 2g protrudes upward from the partition wall 2c.

[0033] A recess 2h is defined radially outward from the bearing bracket 2g by the housing 2 (circumferential wall portion 2a, partition wall portion 2c, and the upper part of the bearing bracket 2g). The shape of the recess 2h is a ring groove that is concave downward. When viewed vertically, the shape of the recess 2h is ring-shaped. That is, the recess 2h is open only upward and has a shape that allows liquid to remain. In other words, a part of the housing 2 (near the partition wall portion 2c) is concave downward, forming the recess 2h. The recess 2h is located radially outward from the bearing bracket 2g and below the motor 4 in the motor chamber R2. The recess 2h has a bottom surface 2h1.

[0034] The shape of the base surface 2h1 is a flat plane parallel to the horizontal direction. The base surface 2h1 is located at the lowest point of the recess 2h. The base surface 2h1 is formed by the upper surface 2c1 of the partition wall portion 2c.

[0035] Pump chamber R1 houses the impeller 7. Pump chamber R1 is located in the lower half of housing 2.

[0036] The motor room R2 houses the motor 4. The motor room R2 is located in the upper half of the housing 2. In other words, the motor room R2 is located above the pump room R1.

[0037] Figure 3 is a partially enlarged cross-sectional view showing part A in Figure 2. In the following explanation, Figures 1 and 2 will be referred to together with Figure 3 as appropriate.

[0038] The discharge member 3 discharges the handling fluid introduced into the motor chamber R2 to the external space (internal space Sc or first internal space Sc1) of the pump 1. The discharge member 3 comprises a first discharge pipe 30, a second discharge pipe 31, a retainer 32, a biasing member 33, a ring member 34, and a plurality of O-rings 35, 36 (two shown in the figure).

[0039] The first outlet pipe 30 is a straight pipe running vertically. The first outlet pipe 30 is inserted into the insertion hole 2e. Specifically, the upper end of the first outlet pipe 30 is positioned (housed) in the first insertion hole 2e1. The lower end of the first outlet pipe 30 is positioned (housed) in the second insertion hole 2e2. The first outlet pipe 30 is provided with an outlet hole 30a.

[0040] The outlet hole 30a is a through-hole that penetrates the wall of the first outlet pipe 30. The outlet hole 30a is located at the top of the first outlet pipe 30. The outlet hole 30a communicates with the upper space R21 of the motor chamber R2, which is located above the motor 4, and with the internal space of the first outlet pipe 30.

[0041] The second outlet pipe 31 is a straight pipe running vertically. The second outlet pipe 31 is inserted through the insertion hole 2e and is positioned below the first outlet pipe 30. Specifically, the upper part of the second outlet pipe 31 is inserted (housed) in the second insertion hole 2e2. The lower part of the second outlet pipe 31 is inserted through the third insertion hole 2e3. In a vertical view, the second outlet pipe 31 is positioned to overlap with the first outlet pipe 30. The second outlet pipe 31 has a lower end 31a, an upper end 31b, and a notch 31c. The lower end 31a protrudes downward from the second flange portion 2d2. A portion of the upper end 31b is notched, forming the notch 31c. The second outlet pipe 31 is movable up and down within the insertion hole 2e, between an elevated position and a lowered position, as long as the second outlet pipe 31 does not protrude from the insertion hole 2e2. That is, the second insertion hole 2e2 accommodates the upper part (part) of the second outlet pipe 31 in a movable manner. The second outlet pipe 31 is an example of an up and down flow path in the present invention.

[0042] The retainer 32 fixes the position of the biasing member 33 in the vertical direction. The retainer 32 has a ring-shaped plate. The retainer 32 is fixed to the outer surface of the second outlet pipe 31. The retainer 32 is positioned between the first flange portion 2d1 and the second flange portion 2d2.

[0043] The biasing member 33 biases the second outlet pipe 31 downward. The biasing member 33 is, for example, a stainless steel coil spring. The second outlet pipe 31 is inserted through the biasing member 33. The biasing member 33 is sandwiched between the first flange portion 2d1 and the retainer 32.

[0044] The ring member 34 interlocks the raising and lowering of multiple second outlet pipes 31. The ring member 34 is shaped like a ring plate. The ring member 34 is attached to the lower end 31a of each second outlet pipe 31. As a result, the portion of the ring member 34 around the lower end 31a functions as a flange portion of the second outlet pipe 31. In other words, this portion is an example of a flange portion in the present invention.

[0045] The O-rings 35 and 36 provide a liquid-tight seal between the second outlet pipe 31 and the second insertion hole 2e2. The O-rings 35 and 36 are positioned above and below the second opening 2f2.

[0046] Motor 4 is driven under predetermined operating conditions to rotate the impeller 7. Motor 4 is a known motor comprising a rotor 41 and a stator 42.

[0047] The rotating shaft 5 rotates due to the rotation of the motor 4 and transmits rotational power to the impeller 7. The shape of the rotating shaft 5 is cylindrical, extending in the vertical direction. The rotating shaft 5 is attached to the rotor 41. The lower half 5a of the rotating shaft 5 extends downward from the motor 4 into the pump chamber R1.

[0048] The bearing 6 rotatably supports the rotating shaft 5. The bearing 6 is, for example, a rolling bearing. The bearing 6 comprises bearings 61 and 62. Bearing 61 is held in bearing bracket 2b1. Bearing 62 is held on the upper part of bearing bracket 2g.

[0049] The impeller 7 is attached to the lower half 5a of the rotating shaft 5 and discharges the liquid being handled, which is drawn in from below, radially outward. The impeller 7 is housed in the pump chamber R1 and is positioned above the suction port 2d3 in the vertical direction.

[0050] The thrust balance mechanism 8 reduces the thrust force (the force pushing the impeller 7 downwards) caused by the pressure difference between the lower and upper sides of the impeller 7. The thrust balance mechanism 8 is a known thrust balance mechanism used in known pumps. The thrust balance mechanism 8 is mounted on the rotating shaft 5 and housed in the lower part of the bearing bracket 2g.

[0051] ● Flow of the fluid being handled in a submerged pump Next, the flow of the liquid being handled in pump 1 when pump 1 is discharging the liquid (when pump 1 is operating) and when pump 1 is lifted will be described below. Figures 1 to 3 will be referred to as appropriate in the following description.

[0052] ● Flow of the fluid being handled when the submerged pump is discharging the fluid Figure 4 is a schematic diagram showing the flow of the liquid being handled when the pump 1 is discharging the liquid.

[0053] When the pump 1 is discharging the liquid being handled (when the pump 1 is operating), the internal space Sc of the pump column T1 is divided into a first internal space Sc1 and a second internal space Sc2 by the second flange portion 2d2 that abuts against the contact surface T1a. At this time, the pump 1 is The pump is positioned in the lowered position. The ring member 34 is in contact with the protrusion T1b and is pressed upward by the protrusion T1b. As a result, the second outlet pipe 31 rises against the biasing force of the biasing member 33 and is in the raised position. The second opening 2f2 is blocked by the upper part of the second outlet pipe 31. That is, the drain hole 2f is not in communication with the second outlet pipe 31. The "raised position" of the second outlet pipe 31 is the position where the second outlet pipe 31 is blocking the second opening 2f2 and is not in communication with the drain hole 2f.

[0054] The liquid being handled inside the storage tank T is drawn into the pump 1 through the inlet 2d3 via the inlet space Sin (flow F1). The liquid being handled drawn into the inlet 2d3 is then drawn into the impeller 7 and discharged into the pump chamber R1 on the downstream side of the impeller 7. Most of the liquid being handled discharged from the impeller 7 is discharged into the second internal space Sc2 through the discharge port 2c3 (flow F2).

[0055] A portion of the fluid discharged from the impeller 7 passes through the thrust balance mechanism 8 and the bearing 62 inside the bearing bracket 2g and is introduced into the motor chamber R2 (flow F3). In other words, the bearing bracket 2g, the bearing 62, and the thrust balance mechanism 8 form a flow path that introduces a portion of the fluid discharged from the impeller 7 from the pump chamber R1 to the motor chamber R2. The bearing bracket 2g, the bearing 62, and the thrust balance mechanism 8 are an example of the first flow path in the present invention. At this time, the fluid functions as a lubricant and coolant for the bearing 62.

[0056] The handling fluid introduced into the motor chamber R2 passes through the motor 4 and is introduced into the upper space R21 (flow F4). At this time, the handling fluid functions as a coolant for the motor 4. The handling fluid that has passed through the motor 4 is led out from the outlet hole 30a to the first outlet pipe 30, and then led out to the first internal space Sc1 via the insertion hole 2e, the first outlet pipe 30, and the second outlet pipe 31 (flow F5). The insertion hole 2e, the first outlet pipe 30, and the second outlet pipe 31 are examples of the second flow path in the present invention.

[0057] A portion of the fluid being handled, discharged from the outlet 2c3 into the second internal space Sc2, passes through the bearing 61 and is introduced into the motor chamber R2 (flow F6). At this time, the fluid being handled functions as both a lubricant and a coolant for the bearing 61.

[0058] Thus, flows F1, F3, F4, and F5 form a circulating flow Fc that lubricates and cools the bearing 62 and the motor 4.

[0059] Here, some of the handling fluid introduced into the motor chamber R2 also flows into the drain hole 2f. As mentioned above, the second opening 2f2 is blocked by the second outlet pipe 31. Therefore, the handling fluid that flows into the drain hole 2f does not flow into the second outlet pipe 31. When the pump 1 is operating, the pressure of the handling fluid introduced into the motor chamber R2 is increased by the impeller 7. Therefore, some of the handling fluid that reaches the second opening 2f2 may seep between the second outlet pipe 31 and the second insertion hole 2e2. However, as mentioned above, in the upward and downward directions of the second opening 2f2, the space between the second outlet pipe 31 and the second insertion hole 2e2 is sealed liquid-tight by O-rings 35 and 36. Therefore, the handling fluid that seeps between the second outlet pipe 31 and the second insertion hole 2e2 does not leak. Therefore, even if a drain hole 2f is formed in this pump 1, the circulating flow Fc is not obstructed, and the performance of this pump 1 does not deteriorate.

[0060] ● Flow of the fluid being handled when the submerged pump is lifted Figure 5 is a partially enlarged cross-sectional view showing part A in Figure 1 when the pump 1 is raised. Figure 6 is a schematic diagram showing the flow of the liquid being handled when the pump 1 is raised.

[0061] Pump 1 is removed from the storage tank T for maintenance, for example. At this time, the operation of pump 1 is stopped. Next, pump 1 is raised to the pump-up position within the internal space Sc until the foot valve T4 closes. At this time, the second flange portion 2d2 does not separate the first internal space Sc1 and the second internal space Sc2. The ring member 34 moves away from the protrusion T1b. As a result, the second outlet pipe 31 is pressed downward by the biasing force of the biasing member 33 and descends from the raised position to the lowered position. The notch 31c of the second outlet pipe 31 moves to a position facing the second opening 2f2. As a result, the drain hole 2f communicates with the second outlet pipe 31. The "lowered position" of the second outlet pipe 31 is the position where the second outlet pipe 31 does not block the second opening 2f2 and communicates with the drain hole 2f.

[0062] Next, an inert gas is introduced into the internal space Sc. At this time, the pressure of the inert gas slightly opens the foot valve T4, and the handling fluid in the internal space Sc is discharged from the inlet space Sin. At this time, the handling fluid remaining in the pump chamber R1 is discharged downward (into the internal space Sc) from the suction port 2d3 (flow F11). Also, the handling fluid remaining in the motor chamber R2 is discharged into the pump chamber R1 through the bearing bracket 2g, bearing 62, and thrust balance mechanism 8 (flow F12), and then discharged downward (into the internal space Sc) through the suction port 2d3 (flow F11) after passing through the pump chamber R1. Finally, the internal space Sc is purged with the inert gas.

[0063] As mentioned above, the recess 2h is recessed downwards. Therefore, some of the handling fluid remaining in the motor chamber R2 remains in the recess 2h. The handling fluid remaining in the recess 2h is discharged into the internal space Sc through the drain hole 2f and the second outlet pipe 31 (flow F13). In this way, when the pump 1 is raised, the handling fluid remaining in the motor chamber R2 (recess 2h) is removed. Therefore, during maintenance of the pump 1, the handling fluid and its vaporized gas do not leak into the external space of the pump 1.

[0064] Thus, the second opening 2f2 of the drain hole 2f is closed when the pump 1 is operating and is open only when the pump 1 is raised. In other words, the drain hole 2f communicates with the external space (internal space Sc) of the pump 1 via the second outlet pipe 31 only when the pump 1 is raised. The second opening 2f2 is opened and closed only by the up and down movement of the second outlet pipe 31. The second outlet pipe 31 moves up and down based solely on the relative magnitudes of the biasing force of the biasing member 33 and the pressing force from the contact surface T1a. In other words, the opening and closing operation of the second outlet pipe 31 is controlled only by the expansion and contraction of the biasing member 33 and the up and down movement of the pump 1. Thus, the pump 1 does not require a complex opening and closing mechanism to open and close the drain hole 2f.

[0065] Most of the fluids handled by this pump 1 are cryogenic liquefied gases. Therefore, if an opening and closing mechanism for the drain hole 2f is attached to this pump 1, the mechanism must be liquid-tight to prevent leakage of the cryogenic and high-pressure fluid into the internal space Sc, and must operate normally and reliably at cryogenic temperatures. Consequently, the manufacture of the opening and closing mechanism is not easy, and the number of man-hours required to attach it to this pump 1 is also high, resulting in high manufacturing costs. In this pump 1, the opening and closing mechanism for the drain hole 2f is configured simply by attaching the second outlet pipe 31, which is part of the path forming the circulating flow Fc, so that it can move up and down, and forming a through hole (drain hole 2f) that communicates with the recess 2h and the second insertion hole 2e2. Therefore, the number of man-hours required to attach the opening and closing mechanism in this pump 1 is relatively small. In addition, the opening and closing operation of the second outlet pipe 31 is controlled only by the expansion and contraction of the biasing member 33 and the raising and lowering of this pump 1, and is not complex. Furthermore, the space between the second insertion hole 2e2 and the second outlet pipe 31 is axially sealed in a liquid-tight manner by O-rings 35 and 36. In other words, in this pump 1, the aforementioned liquid tightness is ensured by local sealing by O-rings 35 and 36. Thus, in this pump 1, the handling fluid remaining in the motor chamber R2 is easily discharged into the internal space Sc without obstructing the circulating flow Fc, thanks to a simple opening and closing mechanism that is both functional and liquid-tight.

[0066] ●Summary According to the embodiment described above, the pump 1 comprises a second flange portion 2d2, a second insertion hole 2e2, a drain hole 2f, a bearing bracket 2g, a recess 2h, a bearing 62, a thrust balance mechanism 8, a first outlet pipe 30, and a second outlet pipe 31. The recess 2h is located in the motor chamber R2. The shape of the recess 2h is a downwardly concave ring groove. The bearing bracket 2g, the bearing 62, and the thrust balance mechanism 8 are located below the motor 4 and function as a first flow path communicating between the pump chamber R1 and the motor chamber R2. The second insertion hole 2e2, the first outlet pipe 30, and the second outlet pipe 31 function as a second flow path communicating between the upper space R21 and the first internal space Sc1. The drain hole 2f communicates with the recess 2h and functions as a third flow path that can communicate with the second outlet pipe 31. The second outlet pipe 31 is movable up and down between an elevated position and a lowered position. The second insertion hole 2e2 houses the upper part of the second outlet pipe 31 in a movable manner. The drain hole 2f has a first opening 2f1 and a second opening 2f2. The first opening 2f1 opens to the bottom surface 2h1, which is located at the lowest point on the inner surface of the recess 2h. The second opening 2f2 opens to the second insertion hole 2e2. When the second flange portion 2d2 is separating the first internal space Sc1 and the second internal space Sc2 (when the pump 1 is operating), the second outlet pipe 31 is in the elevated position and is blocking the second opening 2f2. When the pump 1 is raised and the second flange portion 2d2 is not separating the first internal space Sc1 and the second internal space Sc2, the second outlet pipe 31 is in the lowered position and is in communication with the drain hole 2f. With this configuration, when the pump 1 is operating, the circulating flow Fc is maintained without obstruction. Also, when the pump 1 is retracted, any handling fluid remaining in the motor chamber R2 (recess 2h) is removed. Therefore, during maintenance of the pump 1, the handling fluid and its vaporized gases do not leak to the outside of the pump 1.

[0067] Furthermore, according to the embodiment described above, the pump 1 is equipped with a biasing member 33. The biasing member 33 biases the second outlet pipe 31 downward. When the second flange portion 2d2 separates the first internal space Sc1 and the second internal space Sc2 (when the pump 1 is operating), the second outlet pipe 31 is positioned in the raised position against the biasing force of the biasing member 33. When the pump 1 is pulled up, the second outlet pipe 31 is biased by the biasing member 33 and moves downward from the raised position to the lowered position. With this configuration, when the pump 1 is pulled up, the second outlet pipe 31 easily and reliably communicates with the drain hole 2f. As a result, in the pump 1, the handling fluid remaining in the motor chamber R2 is easily discharged into the internal space Sc without the use of a complex opening and closing mechanism.

[0068] Furthermore, according to the embodiment described above, the outlet member 3 includes a ring member 34 positioned at the lower end 31a of the second outlet pipe 31. When the second flange portion 2d2 is separating the first internal space Sc1 and the second internal space Sc2 (when the pump 1 is operating), the ring member 34 is in contact with the projection T1b and is pressed upward by the projection T1b. When the pump 1 is pulled up, the ring member 34 separates from the projection T1b. With this configuration, the second outlet pipe 31 can be easily raised and lowered.

[0069] Furthermore, according to the embodiment described above, the housing 2 is provided with a plurality of through holes 2e and a plurality of outlet members 3. The ring member 34 is attached to the lower end 31a of each second outlet pipe 31. With this configuration, the raising and lowering of each second outlet pipe 31 is interlocked with each other.

[0070] ●Other embodiments In this invention, the configuration of the first flow path (bearing bracket 2g, bearing 62, and thrust balance mechanism 8) is not limited to this embodiment.

[0071] Furthermore, in the present invention, the number of recesses 2h is not limited to "1". In this case, the housing 2 may be provided with a corresponding drain hole 2f for each recess 2h.

[0072] Furthermore, in the present invention, the position of the recess 2h is not limited to the radially outward direction of the bearing bracket 2g.

[0073] Furthermore, in the present invention, the number of outlet members 3 (second flow path), insertion holes 2e, and drain holes 2f (third flow path) is not limited to "2".

[0074] Furthermore, the shape of the drain hole 2f in the radial view is not limited to an "L" shape. That is, for example, the drain hole 2f may be inclined with respect to the radial direction such that the second opening 2f2 is at the lowest end of the drain hole 2f.

[0075] Furthermore, in the present invention, the first outlet pipe 30 may also be a through hole formed in the housing 2.

[0076] Furthermore, in the present invention, the second outlet pipe 31 does not need to have a notch 31c. In this case, when the second outlet pipe 31 is in the lowered position, the upper end portion 31b of the second outlet pipe 31 is located below the second opening 2f2.

[0077] Furthermore, in the present invention, the outlet member 3 may also include a restricting member that restricts movement below the lowered position of the second outlet pipe 31.

[0078] Furthermore, in the present invention, the lead member 3 does not necessarily have to include a biasing member 33. In this case, the weight of the second lead pipe 31 and / or the ring member 34 should be designed to be such that the second lead pipe 31 can move to the lowered position by its own weight.

[0079] Furthermore, in the present invention, the outlet member 3, the first outlet pipe 30, may be formed integrally with the second outlet pipe 31. In this case, the first outlet pipe 30 has a through hole that can communicate with the second opening 2f2. When the first outlet pipe 30 is in the raised position, the first outlet pipe 30 closes the second opening 2f2, and when the first outlet pipe 30 is in the lowered position, the first outlet pipe 30 communicates with the drain hole 2f.

[0080] Furthermore, in a vertical view, the second outlet pipe 31 in the present invention only needs to be in communication with the first outlet pipe 30, and does not need to be arranged in a way that overlaps with the first outlet pipe 30.

[0081] Furthermore, in the present invention, the biasing member 33 may be positioned between the second flange portion 2d2 and the ring member 34.

[0082] Furthermore, in the present invention, the outlet member 3 does not necessarily have to include the ring member 34. In this case, the outer circumferential surface of the lower end portion 31a of the second outlet pipe 31 may have a flange portion that protrudes radially outward from the second outlet pipe 31. In this configuration, the flange portion abuts against the protruding portion T1b.

[0083] Furthermore, in the present invention, the number of impellers 7 is not limited to "1".

[0084] ●Embodiments of the present invention● Next, embodiments of the present invention as understood from the embodiments described above will be described below, with reference to the terms and reference numerals described in each embodiment.

[0085] A first embodiment of the present invention is a submerged pump (e.g., the pump 1) housed in a cylindrical pump column (e.g., pump column T1) and immersed in a handling fluid, comprising a motor (e.g., motor 4), a rotating shaft (e.g., rotating shaft 5) attached to the motor, an impeller (e.g., impeller 7) attached to the rotating shaft, and a housing (e.g., housing 2) housing the rotating shaft and the impeller, wherein the housing abuts against the pump column and provides an internal space (e.g., internal space Sc) of the pump column, a first internal space (e.g., the A contact portion (e.g., second flange portion 2d2) that divides an internal space (Sc1) and a second internal space (e.g., second internal space Sc2) located above the first internal space, a motor chamber (e.g., motor chamber R2) in which the motor is housed, a pump chamber (e.g., pump chamber R1) located below the motor chamber in which the impeller is housed, a recess (e.g., recess 2h) located in the motor chamber and concave downwards, and a first flow path (e.g., bearing bracket 2) located below the motor that communicates with the motor chamber and the pump chamber. The pump chamber comprises a bearing 62 and a thrust balance mechanism 8), an upper space (e.g., upper space R21) located above the motor in the pump chamber, and at least one second flow path (e.g., insertion hole 2e, first outlet pipe 30, and second outlet pipe 31) communicating with the first internal space, and a third flow path (e.g., drain hole 2f) communicating with the recess and able to communicate with the second flow path, wherein the liquid being drawn into the submerged pump can flow into the first internal space, and the liquid being discharged from the submerged pump flows into the second internal space. The handling fluid can flow into the second flow path, and the second flow path comprises a lifting flow path (e.g., a second outlet pipe 31) that can move up and down between an elevated position and a lowered position, and a housing flow path (e.g., a second insertion hole 2e2) that can move up and down to accommodate a part of the lifting flow path, and the third flow path comprises a first opening (e.g., a first opening 2f1) that opens to the lowest part of the inner surface of the recess (e.g., the bottom surface 2h1), and a second opening (e.g., a second opening 2f2) that opens to the housing flow path, and when the contact portion partitions the first internal space and the second internal space, the lifting flow path isWhen positioned in the raised position, blocking the second opening, and the submerged pump is pulled up so that the contact portion does not partition the first internal space and the second internal space, the lifting and lowering passage is a submerged pump positioned in the lowered position and communicating with the third passage. With this configuration, when the pump is retracted, any handling fluid remaining in the motor chamber (recess) is removed.

[0086] A second embodiment of the present invention is a submerged pump in which, in the first embodiment, the housing comprises a biasing member (for example, biasing member 33) that biases the lifting passage downward, and when the submerged pump is lifted, the lifting passage is biased by the biasing member and descends from the raised position to the lowered position. With this configuration, when the pump is pulled up, the second outlet pipe easily and reliably communicates with the drain hole.

[0087] A third embodiment of the present invention is a submerged pump in which, in the first embodiment, the housing comprises a flange portion (e.g., a ring member 34) disposed at the lower end (e.g., lower end 31a) of the second flow path, and the pump column comprises a contact surface (e.g., contact surface T1a) that contacts the contact portion, and a projection (e.g., projection T1b) that is disposed in the vertical direction below the contact surface and inward from the contact surface of the pump column, and when the contact portion divides the first internal space and the second internal space, the flange portion contacts the projection and is pressed upward, and when the submerged pump is pulled up, the flange portion separates from the projection. With this configuration, the second outlet pipe can be easily raised and lowered.

[0088] A fourth embodiment of the present invention is a submerged pump in which, in the third embodiment, the housing comprises a ring member (for example, a ring member 34) connected to the lower end of the second flow path, the housing comprises a plurality of the second flow paths, and a part of the ring member functions as the flange portion. In this configuration, the raising and lowering of each second outlet pipe is interconnected. [Explanation of Symbols]

[0089] 1 pump (submerged pump) 2 cabinets 2e Through hole (second channel) 2e2 Second insertion hole (containment channel) 2f Drain hole (third channel) 2f1 1st opening 2f2 2nd opening 2g bearing bracket (first flow path) 2h recess 2h1 Base (the part located at the very bottom) 30. First outlet pipe (second channel) 31. Second outlet pipe (second flow path, lifting / lowering flow path) 31a Lower end 33. Biasing member 34 Ring component (flange portion) 20 Pump Room 21 Motor Room 4 motors 5. Rotation axis 62 Bearing (first flow path) 7 Impeller 8. Thrust balance mechanism (second channel) R1 Pump Room R2 Motor Room R21 Upper space Sc internal space Sc1 1st internal space Sc2 2nd internal space T1 Pump Column T1a Contact surface T1b protrusion

Claims

1. A submerged pump housed in a cylindrical pump column and immersed in the fluid being handled, Motor and, A rotating shaft attached to the motor, An impeller attached to the aforementioned rotating shaft, A housing that houses the rotating shaft and the impeller, It has, The aforementioned enclosure is A contact portion that abuts against the pump column and divides the internal space of the pump column into a first internal space and a second internal space located above the first internal space, A motor chamber in which the motor is housed, A pump chamber is located below the motor chamber and houses the impeller, Arranged in the motor chamber, with a recessed area facing downwards, A first flow path is positioned below the motor and communicates with the motor chamber and the pump chamber, The pump chamber comprises an upper space located above the motor and the first internal space, and at least one second flow path communicating with the upper space and the first internal space. A third channel is provided that communicates with the recess and is capable of communicating with the second channel, Equipped with, The first internal space is into which the liquid being handled, which is drawn into the submerged pump, can flow. The second internal space is into which the liquid being handled, discharged from the submerged pump, can flow. The second channel is, A lifting channel that can move up and down between an upward position and a downward position, A housing channel that houses a portion of the aforementioned lifting channel so that it can be raised and lowered, Equipped with, The third channel is, A first opening is provided on the inner surface of the recess, specifically in the portion located at the bottom. A second opening that opens into the aforementioned storage channel, Equipped with, When the contact portion separates the first internal space and the second internal space, the lifting channel is positioned in the raised position and closes the second opening. When the submerged pump is raised and the contact portion no longer divides the first internal space and the second internal space, the lifting passage is positioned in the lowered position and communicates with the third passage. Submerged pump.

2. The aforementioned enclosure is A biasing member that biases the aforementioned lifting channel downwards, Having, When the submerged pump is raised, the lifting passage is biased by the biasing member and descends from the raised position to the lowered position. The submerged pump according to claim 1.

3. The aforementioned enclosure is A flange portion located at the lower end of the second flow path, Equipped with, The aforementioned pump column is The contact surface that contacts the aforementioned contact portion, In the vertical direction, a protrusion is positioned below the contact surface and inward from the contact surface relative to the pump column, Equipped with, When the contact portion separates the first internal space and the second internal space, the flange portion abuts against the protruding portion and is pressed upward. When the submerged pump is lifted, the flange portion separates from the protruding portion. The submerged pump according to claim 1.

4. The aforementioned enclosure is A ring member connected to the lower end of the second flow path, Equipped with, The aforementioned enclosure is Multiple of the above-mentioned second channels, Equipped with, A portion of the ring member functions as the flange portion. The submerged pump according to claim 3.

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