Connection pipe for submersible pump and submersible pump unit

Abstract

To adjust the center of gravity of a submersible pump unit connected to a fixed pipe.SOLUTION: A connection pipe 6 or 7 is interposed between an inlet 21 of a fixed pipe 2 installed in a liquid storage tank, and a discharge port 423 of a submersible pump 4, establishes communication between the inlet and the discharge port, and comprises a pipe body 60 or 70 comprising a first opening 61 or 71 connected to the discharge port, and a second opening 62 or 72 located on the side opposite to the first opening, and connected to the inlet. A first central axis C1 of the first opening 61 and a second central axis C2 of the second opening 62 intersect with each other when the pipe body 60 is viewed in a planar view, or a first central axis C1 of the first opening 71 and a second central axis C2 of the second opening 72 are parallel to each other when the pipe body 70 is viewed in a planar view.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed herein relates to a connecting pipe for a submersible pump and a submersible pump unit. [Background technology]

[0002] Patent Document 1 describes a conventional attachment / detachment device for a submersible pump. The attachment / detachment device includes a connecting straight pipe fixed to the discharge port of the submersible pump. The submersible pump is lowered along a guide pipe within a sewage tank. The connecting straight pipe automatically connects the discharge port of the submersible pump to a discharge pipe installed in the sewage tank.

[0003] Patent Document 2 describes a valve device attached to a submersible pump. The valve device is attached to the outer circumferential surface of the pump casing of the submersible pump. The valve device opens when the submersible pump starts operating, and discharges at least a portion of the discharge flow from the submersible pump into the water tank. The discharge flow agitates the liquid in the liquid storage tank. The valve device closes a certain time after opening, and stops the discharge of the discharge flow. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-135968 [Patent Document 2] Japanese Patent Application Publication No. 2019-78355 Summary of the Invention [Problem to be solved by the invention]

[0005] When a heavy object such as the valve device described above is attached to a submersible pump, the center of gravity of the submersible pump unit, including the submersible pump and the heavy object, shifts from the center of gravity of the submersible pump alone. Specifically, the center of gravity of the submersible pump alone is located on or near the central axis of the submersible pump's discharge port when the submersible pump is viewed in a plan view. In contrast, the center of gravity of the submersible pump unit, including the submersible pump and the heavy object, shifts from the central axis of the discharge port when the submersible pump is viewed in a plan view. Note that, hereinafter, the central axis of the discharge port is defined as a horizontal line that passes through the center of the discharge port opening and passes through the center of gravity of the submersible pump alone when viewed in a plan view, and is referred to as the discharge port central axis.

[0006] A connecting pipe that connects the discharge port of a submersible pump to the inlet of a fixed pipe installed in a liquid storage tank has conventionally extended along the central axis of the discharge port of the submersible pump, as in the connecting straight pipe of Patent Document 1. With the connecting pipe extending along the central axis of the discharge port, the central axis of the inlet of the fixed pipe (hereinafter referred to as the inlet central axis) and the central axis of the discharge port coincide in a planar view. Therefore, the center of gravity of the submersible pump unit is located at a position offset from the inlet central axis when the submersible pump is viewed in a planar view.

[0007] If the center of gravity of the submersible pump unit is offset from the central axis of the inlet in a plan view, a twisting force around the central axis of the inlet constantly acts on the connection between the fixed pipe and the connecting pipe. Misalignment of the center of gravity of the submersible pump unit may cause the submersible pump unit to tilt when subjected to external forces such as earthquakes, or when the submersible pump is repeatedly started and stopped, or when the valve device is repeatedly opened and closed. Furthermore, in a configuration in which the fixed pipe and the connecting pipe are automatically connected, such as that described in Patent Document 1, misalignment of the center of gravity of the submersible pump unit may cause the connection to be released.

[0008] The technology disclosed herein adjusts the center of gravity of a submersible pump unit connected to a fixed pipe. [Means for solving the problem]

[0009] The technology disclosed herein relates to a connecting pipe for a submersible pump. The connecting pipe for a submersible pump is a connecting pipe that is interposed between an inlet of a fixed pipe installed in a liquid storage tank and a discharge port of a submersible pump that is immersed in the liquid storage tank, and that connects the inlet and the discharge port. This connecting pipe is a pipe body having a first opening connected to the discharge port and a second opening located on the opposite side of the first opening and connected to the inlet, The second central axis of the second opening and the central axis of the outlet, which is a straight line connecting the center of the outlet and the center of gravity of the submersible pump, are configured to intersect when the pipe body is viewed in a plane.

[0010] The submersible pump is connected to the fixed pipe via a connecting pipe. The second central axis of the second opening of the pipe body and the central axis of the outlet of the outlet to which the first opening is connected intersect when the pipe body is viewed in a plane. Because the second opening is connected to the inlet of the fixed pipe, the second central axis of the second opening and the central axis of the inlet of the fixed pipe coincide when viewed in a plane. The central axis of the outlet is a line connecting the center of the outlet and the center of gravity of the submersible pump, and the first central axis of the first opening and the central axis of the outlet coincide when viewed in a plane. Here, as described below, for a submersible pump whose outlet opens vertically upward, the first opening opens vertically downward. Even in this structure, when the connecting pipe is connected to the outlet, the first central axis and the central axis of the outlet coincide when viewed in a plane.

[0011] By using the connecting pipe with the above configuration, the central axis of the outlet of the submersible pump and the central axis of the inlet of the fixed pipe intersect when the submersible pump is viewed in plan view. In other words, when viewed in plan view, the submersible pump is connected to the fixed pipe in a state where it is tilted with respect to the central axis of the inlet of the fixed pipe.

[0012] Consider a case where the center of gravity of the submersible pump unit, including the submersible pump and the heavy load, is shifted from the central axis of the discharge port due to the attachment of a heavy load to the submersible pump. The use of the connecting pipe tilts the submersible pump relative to the central axis of the inlet of the fixed pipe in a plan view, so that the center of gravity of the submersible pump unit can be positioned on or closer to the central axis of the inlet. The connecting pipe can adjust the center of gravity of the submersible pump unit connected to the fixed pipe in a plan view.

[0013] If the center of gravity of the underwater pump unit is located on or close to the central axis of the inlet when viewed in a plane, twisting forces around the central axis of the inlet are prevented from acting on the connection point between the fixed piping and the connecting pipe.

[0014] When connected to the outlet, the first opening and the second opening may both open horizontally, and the second central axis of the second opening and the central axis of the outlet may be configured to intersect when the pipe body is viewed in a plane.

[0015] The discharge port of the submersible pump opens vertically upward, When connected to the discharge port, the second opening may open horizontally, the first opening may open vertically downward, and the second central axis of the second opening and the discharge central axis may be configured to intersect when the pipe body is viewed in a plane.

[0016] Another connector disclosed herein is a pipe body having a first opening connected to the discharge port and a second opening located on the opposite side of the first opening and connected to the inlet, A first central axis of the first opening and a second central axis of the second opening are parallel to but do not coincide with each other when the pipe body is viewed from above.

[0017] The first central axis of the first opening of the pipe body and the second central axis of the second opening are parallel but not coincident when the pipe body is viewed in a plane. When the submersible pump is connected to the fixed pipe via the connecting pipe, the central axis of the discharge port of the submersible pump and the central axis of the inlet of the fixed pipe are parallel but not coincident when the submersible pump is viewed in a plane. In other words, the submersible pump is connected to the fixed pipe in a state where it is horizontally shifted parallel to the inlet of the fixed pipe.

[0018] If the center of gravity of the submersible pump unit is shifted from the central axis of the discharge port due to the attachment of a heavy load to the submersible pump, the use of the connecting pipe allows the submersible pump to move horizontally parallel to the inlet of the fixed pipe, so that the center of gravity of the submersible pump unit can be positioned on or closer to the central axis of the inlet. The connecting pipe allows the center of gravity of the submersible pump unit to be adjusted when connected to the fixed pipe.

[0019] Furthermore, if the center of gravity of the underwater pump unit is located on or close to the central axis of the inlet when viewed in a plane, twisting forces acting around the central axis of the inlet at the connection point between the fixed piping and the connecting pipe are suppressed.

[0020] The connecting pipe is a flange in which the first opening is formed and which is fixed to the submersible pump; a slider that is integrated with at least one of the flange and the pipe body, and that moves up and down along a guide that extends vertically in the liquid storage tank while being engaged with the guide; The pipe body attached to the submersible pump via the flange descends together with the submersible pump to a bottom position in the liquid storage tank; The second opening may be connected to the inlet when the submersible pump is positioned in the bottom position.

[0021] The connecting pipe fixed to the submersible pump may have the function of guiding the submersible pump's raising and lowering within the liquid storage tank using a slider, and the function of automatically connecting and disconnecting the submersible pump to the fixed pipe.

[0022] The guide includes a pair of guides arranged at an interval in an orthogonal direction perpendicular to the connection direction between the fixed pipe and the submersible pump and the vertical direction, The connecting pipe may further include a regulating portion located between the pair of guides and spaced apart vertically from the slider, and which contacts the guides to prevent the underwater pump connected to the fixed pipe from tilting in the perpendicular direction.

[0023] As mentioned above, if the center of gravity of the submersible pump unit, which includes the submersible pump and a heavy object (e.g., a valve device), is offset from the central axis of the discharge port in a plan view, the restricting portion will come into contact with a pair of guides even if the submersible pump unit attempts to tilt perpendicularly when an external force such as an earthquake is applied, or when the submersible pump is started / stopped or the valve device is opened / closed. The contact between the restricting portion and the guides prevents the submersible pump unit from tilting further. The connection between the submersible pump and the fixed piping is maintained stably.

[0024] The submersible pump unit disclosed herein comprises: The connecting pipe; and a submersible pump to which the connecting pipe is attached.

[0025] The submersible pump unit further comprises an accessory device fixed to the submersible pump; The center of gravity of the accessory device may be positioned offset from a straight line connecting the center of gravity of the submersible pump and the center of the discharge port when the submersible pump is viewed in a plane.

[0026] The center of gravity of the submersible pump unit, including the submersible pump and accessories, is offset from the central axis of the discharge port in plan view. The connecting pipe described above can position the center of gravity of the submersible pump unit connected to the fixed pipe on the central axis of the inlet in plan view, or close to the central axis of the inlet. This prevents twisting forces from acting around the central axis of the inlet at the connection point between the fixed pipe and the connecting pipe.

[0027] When the submersible pump is connected to the fixed piping via the connecting pipe, the center of gravity of the submersible pump unit including the submersible pump and the accessory equipment may be located on the second central axis or close to the second central axis when the submersible pump is viewed in a plane.

[0028] The use of the connecting pipe adjusts the center of gravity of the submersible pump unit when it is connected to the fixed pipe. [Effects of the Invention]

[0029] As described above, the connecting pipe can adjust the center of gravity of the submersible pump unit connected to the fixed pipe. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a side view of the submersible pump unit. [Figure 2] FIG. 2 is a plan view of the submersible pump unit. [Figure 3] The left diagram in FIG. 3 is a front view of the connecting pipe, and the right diagram is a plan view of the connecting pipe. [Figure 4] FIG. 4 is a plan view of a submersible pump unit according to a modified example. [Figure 5] FIG. 5 is a plan view of a connecting pipe according to a modified example. [Figure 6] FIG. 6 is a side view of a submersible pump unit according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, embodiments of a connecting pipe for a submersible pump and a submersible pump unit will be described with reference to the drawings. The connecting pipe for a submersible pump and the submersible pump unit described here are examples.

[0032] (Overall configuration of submersible pump unit) Fig. 1 is a side view of the submersible pump unit 1. Fig. 2 is a plan view of the submersible pump unit 1. Note that in Fig. 1, of a pair of guides 3 described below, the guide 3 located at the front is omitted.

[0033] The submersible pump unit 1 is installed in a liquid storage tank. The liquid storage tank is, for example, a sewage relay pump tank. The submersible pump unit 1 is connected to a fixed pipe 2. The submersible pump unit 1 operates automatically when the level of sewage flowing into the liquid storage tank reaches or exceeds a predetermined operating level. The submersible pump unit 1 discharges the sewage out of the liquid storage tank via the fixed pipe 2.

[0034] The fixed pipe 2 is fixed in advance in the liquid storage tank. The fixed pipe 2 extends in the vertical direction Z. The lower end of the fixed pipe 2 is formed by a vent pipe, and the inlet 21 of the fixed pipe 2 faces horizontally, more specifically, in the connection direction X of the fixed pipe 2 and the submersible pump unit 1.

[0035] A guide 3 is pre-disposed within the liquid storage tank. The guide 3 also extends in the vertical direction Z. The lower end of the guide 3 is fixed to the lower end of the fixed pipe 2. As shown in FIG. 2, the guide 3 includes a pair of guides 3. The pair of guides 3 are aligned at a distance from each other in an orthogonal direction Y that is orthogonal to the vertical direction Z and the connection direction X. The pair of guides 3 are positioned so as to be axially symmetrical with respect to the central axis of the inlet 21 of the fixed pipe 2, i.e., the inlet central axis C2, in a plan view, with the central axis of the inlet 21, i.e., the inlet central axis C2, sandwiched between them. The guides 3, 3 guide the submersible pump unit 1 as it moves up and down within the liquid storage tank.

[0036] The submersible pump unit 1 includes a submersible pump 4. The submersible pump 4 includes a motor section 41 and a pump section .

[0037] The motor section 41 has a motor and a motor casing 411 that houses the motor. The motor's rotation shaft extends in the vertical direction Z. An eyebolt 412 is attached to the upper end of the motor casing 411. The lower end of a lifting chain is engaged with the eyebolt 412. The submersible pump unit 1 moves up and down within the liquid storage tank while suspended from the lifting chain. The eyebolt 412 is located at a position offset from the center of gravity G1 of the submersible pump 4. The position of the center of gravity G1 of the submersible pump 4 coincides or nearly coincides with the rotation shaft of the motor.

[0038] The pump section 42 is located below the motor section 41. The pump section 42 has an impeller and a pump casing 421 that houses the impeller. The submersible pump 4 is a centrifugal pump. The pump casing 421 is of a spiral type. The suction port of the pump casing 421 opens downward. In FIG. 1, a bell mouth 422 is attached to the suction port of the pump casing 421. The discharge port 423 of the pump casing 421 opens horizontally, as shown in FIG. 2.

[0039] The submersible pump unit 1 is equipped with a valve device 5. The valve device 5 is an example of an accessory device. When the submersible pump 4 starts operating, the valve device 5 discharges part or all of the discharge flow of the submersible pump 4 into the liquid storage tank. The valve device 5 is an in-tank agitation device. Note that in FIG. 1, the valve device 5 has been removed to facilitate understanding of the technology disclosed herein.

[0040] The valve device 5 is attached to the side of the pump casing 421. The pump casing 421 has an attachment portion 424 for the valve device 5 near the discharge port 423. The attachment portion 424 has a branch hole 425 that communicates with the interior of the pump casing 421. The valve device 5 attached to the attachment portion 424 communicates with the branch hole 425. As shown in Figure 2, the valve device 5 protrudes outward from the outer periphery of the pump casing 421. When the submersible pump 4 is viewed from above, the center of gravity of the valve device 5 is positioned offset from the straight line L1 that connects the center of the discharge port 423 and the center of gravity G1 of the submersible pump 4.

[0041] The valve device 5 is a relatively large and heavy object. The center of gravity G2 of the submersible pump unit 1, which includes the submersible pump 4 and the valve device 5, is shifted toward the valve device 5 with respect to the center of gravity G1 of the submersible pump 4. More specifically, when the submersible pump 4 is viewed in a plan view, the center of gravity G2 of the submersible pump unit 1 is shifted toward the valve device 5 with respect to the straight line L1.

[0042] (Configuration of connecting pipe) The submersible pump unit 1 is equipped with a connecting pipe 6. The connecting pipe 6 is interposed between the inlet 21 of the fixed pipe 2 and the discharge port 423 of the submersible pump 4, and connects the inlet 21 and the discharge port 423. Figure 3 shows an enlarged view of the connecting pipe 6.

[0043] The connecting pipe 6 has a pipe body 60. The pipe body 60 has a first opening 61 and a second opening 62. The first opening 61 opens at a first end of the pipe body 60 in the connecting direction. The first opening 61 is connected to the discharge port 423. The pipe body 60 has a flange 63. The flange 63 is fixed to the pump casing 421. The first opening 61 is formed in the flange 63. The second opening 62 opens at a second end of the pipe body 60 in the connecting direction X. The second end is the end opposite to the first end in the connecting direction X. The second opening 62 is connected to the inlet 21.

[0044] The first central axis of the first opening 61 is coaxial with the line connecting the center of the outlet 423 of the submersible pump 4 and the center of gravity of the submersible pump 4, i.e., the outlet central axis. The first central axis and the outlet central axis coincide in a planar view. Hereinafter, the first central axis and the outlet central axis will be referred to as the first central axis C1. Note that the first central axis C1 substantially coincides with the aforementioned line L1. The second central axis of the second opening 62 is coaxial with the inlet central axis C2 of the fixed pipe 2. The second central axis and the inlet central axis C2 coincide in a planar view. Hereinafter, the second central axis and the inlet central axis will be referred to as the second central axis C2. As shown in FIG. 3, the flange 63 is inclined with respect to the connection direction X. Due to the inclination of the flange 63, the second central axis C2 of the second opening 62 is inclined with respect to the first central axis C1 of the first opening 61. In other words, the first central axis C1 of the first opening 61 and the second central axis C2 of the second opening 62 are not coaxial. The first central axis C1 of the first opening 61 (in other words, the central axis of the outlet) and the second central axis C2 of the second opening 62 intersect when the pipe body 60 is viewed in a plane.

[0045] Because the flange 63 is tilted, the submersible pump 4 is tilted by an angle θ relative to the fixed pipe 2 in a plan view, as shown in FIG. 2. The submersible pump unit 1, including the submersible pump 4 and the valve device 5, has a center of gravity G2 that is offset from the center of gravity G1 of the submersible pump 4. However, the center of gravity G2 of the submersible pump unit 1 is located on or near the second central axis C2, as shown in FIG. 2. This prevents twisting forces from acting around the second central axis C2 at the connection between the fixed pipe 2 and the connecting pipe 6. Because the center of gravity G2 is located on or near the second central axis C2, tilting of the submersible pump 4 is prevented even when an external force such as an earthquake is applied, the submersible pump 4 is repeatedly started and stopped, or the valve device 5 is repeatedly opened and closed. This also prevents the connection between the fixed pipe 2 and the connecting pipe 6 from being released.

[0046] The connecting pipe 6 also has a slider 64. The slider 64 moves in the vertical direction Z along the guide 3. As the slider 64 moves in the vertical direction Z along the guide 3, the submersible pump unit 1 rises and falls along the guide 3. The slider 64 is integrated with the flange 63 and extends in the perpendicular direction Y so as to bridge between a pair of guides 3 aligned in the perpendicular direction Y. The slider 64 has an arc-shaped engagement recess 65 that surrounds the periphery of the guide 3, which has a circular cross section. The slider 64 has two engagement recesses 65 corresponding to each of the pair of guides 3. The slider may be integrated with at least one of the flange 63 and the pipe main body 60.

[0047] As shown in FIG. 1 , the connecting pipe 6 has a hook 66 for automatically connecting the submersible pump unit 1 to the fixed pipe 2. The hook 66 is provided facing downward on the underside of the slider 64. An engaging protrusion 22 is formed at the tip where the inlet 21 of the fixed pipe 2 is formed. When the submersible pump unit 1 is lowered and the hook 66 engages with the engaging protrusion 22 from above, the second opening 62 of the connecting pipe 6 is automatically connected to the inlet 21 of the fixed pipe 2 as the weight of the submersible pump unit 1 presses the engaging portion against the fulcrum. In a plan view, the center of gravity G2 of the submersible pump unit 1 is located on or near the second central axis C2, so that the second opening 62 is pressed straight and stably against the inlet 21. Furthermore, when the underwater pump is operated, the discharge pressure generates a force that tries to lift the underwater pump unit 1 with the engagement portion as a fulcrum and a force that tries to press it against the center of the second opening 62, and these forces act on the same line in a plan view, thereby suppressing the moment around the vertical axis and stabilizing the connection.

[0048] 2, the eyebolt 412 is located on or near the second central axis C2 in a plan view. When the submersible pump unit 1 is raised and lowered using a lifting chain engaged with the eyebolt 412, the submersible pump unit 1 can be raised and lowered stably by the lifting chain.

[0049] The connecting pipe 6 further has a regulating portion 67. The regulating portion 67 regulates the submersible pump unit 1 connected to the fixed pipe 2 from tilting in the orthogonal direction Y. The regulating portion 67 is located between a pair of guides 3, 3 aligned in the orthogonal direction Y. The regulating portion 67 is also located above and spaced apart from the slider 64 in the vertical direction Z. The regulating portion 67 is supported by a support portion 68 extending upward from the slider 64 in the vertical direction Z. The regulating portion 67 has a substantially rectangular shape in plan view. When the submersible pump unit 1 attempts to tilt in the orthogonal direction Y, the regulating portion 67 comes into contact with the guide 3, thereby regulating the tilt of the submersible pump unit 1. Because the slider 64, which engages with the guide 3, and the regulating portion 67 are spaced apart in the vertical direction Z, the regulating portion 67 can effectively regulate the tilt of the submersible pump unit 1 in the orthogonal direction Y.

[0050] The regulating portion 67 does not have a portion that engages with the guide 3, like the engaging recess 65 of the slider 64. Both side edges of the regulating portion 67 in the orthogonal direction Y extend straight in the connection direction X. The regulating portion 67 does not interfere with the guide 3 in the connection direction X. Therefore, even if the submersible pump unit 1 tilts in the connection direction X when rising and falling along the guide 3, the regulating portion 67 does not restrict the tilt of the submersible pump unit 1. If both the slider 64 and the regulating portion 67 restricted the tilt of the submersible pump unit 1, the connecting pipe 6 would get caught on the guide 3 during the rise and fall of the submersible pump unit 1, preventing the submersible pump unit 1 from rising and falling smoothly. Because the regulating portion 67 does not interfere with the guide 3 in the connection direction X, the submersible pump unit 1 can rise and fall smoothly.

[0051] (Variation) 4 and 5 show modified examples of the connecting pipe. In this connecting pipe 7, the first central axis C1 of the first opening 71 and the second central axis C2 of the second opening 72 are parallel to but do not coincide with each other when the pipe body 70 is viewed in plan. In other words, the first central axis C1 of the first opening 71 and the second central axis C2 of the second opening 72 are offset by a distance D in the orthogonal direction Y. The flange 73 is orthogonal to the connecting direction X.

[0052] Because the flange 73 is not tilted, the submersible pump 4 does not tilt relative to the fixed pipe 2, as shown in FIG. 4 . However, because the first central axis C1 of the first opening 71 is offset in the perpendicular direction Y relative to the second central axis C2 of the second opening 72, the submersible pump 4 moves parallel to the fixed pipe 2 by a distance D in the perpendicular direction Y. The center of gravity G2 of the submersible pump unit 1, including the submersible pump 4 and the valve device 5, is located on or near the second central axis C2. This prevents twisting forces from acting around the second central axis C2 at the connection between the fixed pipe 2 and the connecting pipe 7. Because the center of gravity G2 is located on or near the second central axis C2, tilting of the submersible pump 4 is prevented even when an external force such as an earthquake is applied, the submersible pump 4 is repeatedly started and stopped, or the valve device 5 is repeatedly opened and closed. This also prevents the connection between the fixed pipe 2 and the connecting pipe 7 from being disconnected.

[0053] Like the connecting pipe 6, the connecting pipe 7 has a slider 74 formed with an engagement recess 75. The slider 74 moves in the vertical direction Z along the guide 3. As shown in FIG. 4, the eyebolt 412 is located on or near the second central axis C2. Even when the connecting pipe 7 is used, the submersible pump unit 1 can be stably raised and lowered by the lifting chain.

[0054] The connecting pipe 7 also has a hook that engages with the engaging protrusion 22 of the fixed pipe 2. The second opening 72 of the connecting pipe 7 is automatically connected to the inlet 21 of the fixed pipe 2. The connecting pipe 7 further has a regulating portion 77. The regulating portion 77 effectively regulates the tilt of the submersible pump unit 1 in the orthogonal direction Y.

[0055] 6 shows yet another modified example of the connecting pipe. The connecting pipe 600 does not include the restricting portion 67 and the supporting portion 68 of the connecting pipe 6. Note that the restricting portion 77 of the connecting pipe 7 may be omitted.

[0056] Furthermore, the sliders 64, 74 and the hook 66 may be omitted from the connecting pipes 6, 7. The technology disclosed herein is not limited to application to an automatic connection type submersible pump unit.

[0057] The technology disclosed herein is not limited to application to submersible pumps with the shapes or structures shown in the figures. The discharge port of a submersible pump may be open vertically upward, in addition to opening horizontally. A connecting pipe connected to a vertically upward discharge port has a second opening opening horizontally and a first opening opening vertically downward. In this connecting pipe, the second central axis of the second opening and the line connecting the center of the discharge port and the center of gravity of the submersible pump, i.e., the central axis of the discharge port, intersect when the pipe body is viewed in plan. A submersible pump connected to a fixed pipe via a connecting pipe is connected to the fixed pipe at an angle with respect to the central axis of the inlet of the fixed pipe when viewed in plan. Therefore, as with the structure described above, the center of gravity of the submersible pump unit can be positioned on or close to the central axis of the inlet.

[0058] Furthermore, the accessory device for the submersible pump is not limited to the valve device 5 . [Explanation of symbols]

[0059] 1 Submersible pump unit 2 Fixed piping 21 Entrance 3 Guide 4. Submersible pump 423 Discharge port 6 Connecting pipe 60 Tube body 61 First Opening 62 Second Opening 63 flange 64 sliders 67 Regulatory Department 600 Connecting Pipe 7 Connecting pipe 70 Tube body 71 First Opening 72 Second Opening 73 flange 74 Slider 77 Regulatory Department C1 1st center axis C2 2nd central axis G1 Submersible Pump Center of Gravity G2 Submersible Pump Unit Center of Gravity X connection direction Y orthogonal direction Z vertical direction

Claims

1. A connecting pipe that is interposed between an inlet of a fixed pipe installed in a liquid storage tank and a discharge port of a submersible pump immersed in the liquid storage tank and that connects the inlet and the discharge port, a pipe body having a first opening connected to the discharge port and a second opening located on the opposite side of the first opening and connected to the inlet, A connecting pipe for an underwater pump, wherein the second central axis of the second opening and the central axis of the outlet, which is a straight line connecting the center of the outlet and the center of gravity of the underwater pump, are configured to intersect when the pipe body is viewed in a plane.

2. The connecting pipe of the submersible pump according to claim 1, A connecting pipe for an underwater pump, wherein when connected to the discharge port, the first opening and the second opening both open horizontally, and the second central axis of the second opening and the central axis of the discharge port intersect when the pipe body is viewed in a plane.

3. The connecting pipe of the submersible pump according to claim 1, The discharge port of the submersible pump opens vertically upward, A connecting pipe for an underwater pump, wherein when connected to the discharge port, the second opening opens horizontally, the first opening opens vertically downward, and the second central axis of the second opening and the central axis of the discharge port intersect when the pipe body is viewed in a plane.

4. A connecting pipe that is interposed between an inlet of a fixed pipe installed in a liquid storage tank and a discharge port of a submersible pump immersed in the liquid storage tank and that connects the inlet and the discharge port, a pipe body having a first opening connected to the discharge port and a second opening located on the opposite side of the first opening and connected to the inlet, A connecting pipe for an underwater pump, wherein the first central axis of the first opening and the second central axis of the second opening are parallel and non-coincident when the pipe body is viewed in a plane.

5. The connecting pipe of the submersible pump according to any one of claims 1 to 4, a flange in which the first opening is formed and which is fixed to the submersible pump; a slider that is integrated with at least one of the flange and the pipe body, and that moves up and down along a guide that extends vertically in the liquid storage tank while being engaged with the guide; The pipe body attached to the submersible pump via the flange descends together with the submersible pump to a bottom position in the liquid storage tank; The second opening is connected to the inlet when the submersible pump is positioned at the bottom position.

6. The connecting pipe of the submersible pump according to claim 5, The guide includes a pair of guides arranged at an interval in an orthogonal direction perpendicular to the connection direction between the fixed pipe and the submersible pump and the vertical direction, A connecting pipe for an underwater pump further comprising a regulating portion positioned between the pair of guides and spaced apart vertically from the slider, and contacting the guides to prevent the underwater pump connected to the fixed pipe from tilting in the perpendicular direction.

7. The connecting pipe according to any one of claims 1 to 4; and a submersible pump to which the connecting pipe is attached.

8. The submersible pump unit according to claim 7, further comprising an accessory device secured to the submersible pump; An underwater pump unit wherein the center of gravity of the accessory device is positioned offset from a straight line connecting the center of gravity of the underwater pump and the center of the discharge port when the underwater pump is viewed in a plane.

9. 9. The submersible pump unit according to claim 8, An underwater pump unit, wherein when the underwater pump is connected to the fixed piping via the connecting pipe, the center of gravity of the underwater pump unit including the underwater pump and the auxiliary equipment is located on the second central axis or close to the second central axis when the underwater pump is viewed in a plane.

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