Centrifugal Pump with Dual-Mode Operation

Abstract

The present invention relates to a centrifugal pump that supports a dual mode, and more specifically, to a centrifugal pump that supports a dual mode that includes an expansion chamber assembly that forms a fluid passage path along the outer circumference of a shaft and opens and closes the said fluid passage path, and a cam actuation module that drives the same, thereby supporting a dual mode that stably transfers fluid in an operating mode and prevents external leakage of fluid in a maintenance mode, which can improve operator safety and increase the reliability of a fluid transfer system.

Description

Technology Field

[0001] The present invention relates to a centrifugal pump that supports a dual mode, and more specifically, to a centrifugal pump that supports a dual mode that includes an expansion chamber assembly that forms a fluid passage path along the outer circumference of a shaft and opens and closes the said fluid passage path, and a cam actuation module that drives the same, thereby supporting a dual mode that stably transfers fluid in an operating mode and prevents external leakage of fluid in a maintenance mode, which can improve operator safety and increase the reliability of a fluid transfer system. Background Technology

[0003] A vertical centrifugal pump has a structure comprising a vertically positioned shaft and an impeller that rotates by the shaft, and operates by pressurizing and discharging the fluid as the impeller rotates. Due to these characteristics, vertical centrifugal pumps are suitable for transporting fluids with low viscosity and that vaporize easily, such as liquefied fuels, and are widely utilized in various industrial fields, including chemical plants, liquefied gas transfer facilities, and power plant cooling systems.

[0005] In particular, for fluids such as liquefied fuels that have low boiling points and can exist as a mixture of liquid and gaseous phases even inside the tank, it is even more critical to reliably control fluid leakage during both operating and maintenance conditions. Since these fluids easily vaporize and convert into gas upon minute temperature or pressure changes, the risk of gas leakage during pump maintenance can be greater than that associated with general liquids.

[0006] Vertical centrifugal pumps handling liquefied fuels must stably transfer the fluid during operation, but it is crucial that they remain securely sealed to prevent the internal fluid from being exposed to the outside during maintenance. In particular, when handling toxic or highly flammable liquefied fuels, even a small gas leak during maintenance can seriously threaten worker safety or lead to major accidents such as explosions. Therefore, the pump must be able to meet different sealing conditions in operating and maintenance modes.

[0008] In conventional vertical centrifugal pumps, various stop sealing methods have been applied to mitigate these problems. For example, methods involving the insertion of elastic elements such as gaskets, packings, or O-rings into the shaft periphery, or methods where gaps are sealed through direct metal-to-metal contact, have been widely used. However, despite the advantage of simple structures, these methods suffer from a problem where sealing performance deteriorates rapidly due to wear and deformation caused by prolonged operation. Furthermore, for liquefied fuels in cryogenic conditions or fuels that vaporize easily at room temperature, it is difficult to guarantee complete sealing due to material shrinkage and expansion or incomplete contact. Moreover, these conventional structures fail to clearly distinguish between operating and maintenance modes, which can lead to minute gas leakage even during maintenance.

[0010] Therefore, there is a need for a vertical centrifugal pump with a new structure that enables normal fluid transfer during operation while reliably blocking any leakage of vaporized fuel to the outside during maintenance.

[0011] delete Prior art literature

[65535] Korean Patent Publication No. 10-2194051 (Mechanical seal for pump, published Dec. 22, 2020) Korean Patent Publication No. 10-1837139 (Centrifugal pump, published Mar. 05, 2018) The problem to be solved

[0012] The present invention aims to provide a centrifugal pump that supports a dual mode, which includes an expansion chamber assembly that forms a fluid passage path along the outer circumference of a shaft and opens and closes the said fluid passage path, and a cam actuation module that drives the same, thereby supporting a dual mode that stably transports fluid in an operating mode and prevents external leakage of fluid in a maintenance mode, which can improve operator safety and increase the reliability of the fluid transfer system. means of solving the problem

[0014] To solve the above problems, one embodiment of the present invention provides a centrifugal pump for pumping fluid from a tank, comprising: a shaft extending into the interior of the tank; a fluid pumping unit connected to the lower end of the shaft to transfer fluid contained in the tank; a driving unit connected to the upper end of the shaft to provide rotational power to the fluid pumping unit; a fluid discharge unit guiding the fluid transferred from the tank to the outside; and an expansion chamber assembly disposed above the fluid discharge unit, forming a fluid passage path along the outer surface of the shaft, and opening and closing the fluid passage path; wherein the expansion chamber assembly operates in one of the following modes: a first mode in which the fluid passage path is opened to allow fluid to move; and a second mode in which the fluid passage path is blocked to prevent fluid from moving.

[0015] In some embodiments of the present invention, the centrifugal pump may further include: a bearing module disposed below the driving unit and rotatably supporting the shaft; and an intermediate housing disposed between the driving unit and the fluid discharge unit and accommodating the expansion chamber assembly and the bearing module in its internal space.

[0016] In some embodiments of the present invention, the expansion seal assembly comprises: a lower flange that receives the shaft in the center; an upper flange that is connected to the lower flange via a connecting means, is spaced upward, receives the shaft in the center, and is positioned to be movable along the shaft; and a seal housing that is spaced upward from the upper flange and fixed to the shaft; wherein a sealing groove is formed on the upper surface of the upper flange and is concave downward along the circumferential direction of the shaft, and a sealing protrusion is formed on the seal housing and protrudes downward along a shape corresponding to the sealing groove.

[0017] In some embodiments of the present invention, when the expansion seal assembly operates in a first mode, the sealing groove of the upper flange and the seal protrusion of the seal housing are spaced apart from each other to open a fluid passage path, and when the expansion seal assembly operates in a second mode, the seal protrusion engages with the inner side of the sealing groove to block the fluid passage path.

[0018] In some embodiments of the present invention, the expansion seal assembly comprises: a lower flange that receives the shaft in the center; an upper flange that is connected to the lower flange via a connecting means, is spaced upward, receives the shaft in the center, and is positioned to be movable along the shaft; a seal housing that is spaced upward from the upper flange and fixed to the shaft; and a cam operating module that moves the upper flange up and down along the shaft; wherein the cam operating module may comprise a rotary rod extended radially along the shaft; a cam member connected to the inner end of the rotary rod and converting the rotational power of the rotary rod into linear movement power; and a follower rod, the lower end of which is connected to the cam member and the upper end of which is connected to the lower end of the upper flange.

[0019] In some embodiments of the present invention, when the rotary rod rotates in one direction, the rotational power is converted into linear movement power by the cam member, thereby moving the upper flange upward along the shaft, so that the expansion chamber assembly operates in a second mode, and when the rotary rod rotates in the other direction, the rotational power is converted into linear movement power by the cam member, thereby moving the upper flange downward along the shaft, so that the expansion chamber assembly operates in a first mode.

[0020] In some embodiments of the present invention, the expansion assembly comprises: a lower flange that receives the shaft in the center; an upper flange that is spaced above the lower flange and receives the shaft in the center and is movably positioned along the shaft; a first bellows member having a first diameter, with its lower end fixed to the lower flange and its upper end fixed to the upper flange; and a second bellows member having a second diameter larger than the first diameter, with its lower end fixed to the lower flange and its upper end fixed to the upper flange; wherein the first bellows member and the second bellows member may be concentrically arranged around the shaft and spaced apart from each other along the radial direction.

[0021] In some embodiments of the present invention, the first bellows member and the second bellows member are each welded at their upper and lower ends to the lower flange and the upper flange, respectively, thereby forming a sealing space between the first bellows member and the second bellows member, and when the upper flange moves upward along the shaft, the volume of the sealing space expands and the pressure in the sealing space decreases, thereby preventing the fluid from flowing out of the fluid passage path. Effects of the invention

[0023] According to one embodiment of the present invention, the expansion seal assembly minimizes friction and surface pressure caused by contact in a first mode and implements sealing only in a second mode, thereby fundamentally reducing the continuous contact section with a high contribution to wear, which can have the effect of increasing the lifespan of the shaft support system.

[0024] According to one embodiment of the present invention, by structurally blocking the fluid passage path in the second mode, the exposure of vaporized fluid to a hazardous environment is completely blocked, thereby enabling the effect of reducing worker safety and environmental leakage risks.

[0025] According to one embodiment of the present invention, the centrifugal pump is applicable to ambient temperature volatile chemicals including vaporizable low-viscosity fluids such as cryogenic LNG, liquid hydrogen, and liquid ammonia, thereby enabling excellent scalability to various facilities such as chemical plants and vessels for liquid fuel.

[0026] According to one embodiment of the present invention, the sealing groove of the upper flange and the sealing protrusion of the seal housing are configured to engage in an annular manner, thereby enabling uniform sealing in all circumferential directions and ensuring stable sealing performance even under eccentricity or local pressure.

[0027] According to one embodiment of the present invention, by having a cam member with a teardrop shape and a roller member disposed at the bottom of a follower rod, linear motion with low friction can be achieved along the cam profile, thereby enhancing the precision and reproducibility of the vertical position control of the upper flange.

[0028] According to one embodiment of the present invention, a first bellows member and a second bellows member are arranged concentrically to form a sealing space between them, and when the upper flange moves upward, the volume of the sealing space expands and the pressure decreases, thereby preventing the fluid from flowing out of the fluid passage path.

[0029] According to one embodiment of the present invention, a bearing module disposed inside a middle housing suppresses runout of the shaft, thereby reducing the occurrence of misalignment at the mating surface between the sealing groove and the sealing protrusion, and can exhibit the effect of preventing uneven wear of the sealing surface.

[0030] According to one embodiment of the present invention, by configuring the system to switch between a first mode and a second mode by operating a rotary rod from the outside, the stopping and maintenance procedures of the pump can be simplified and the turnaround time can be shortened. Brief explanation of the drawing

[0032] FIG. 1 schematically illustrates a perspective view of a centrifugal pump according to one embodiment of the present invention. FIG. 2 schematically illustrates an enlarged cross-sectional view of the intermediate housing side according to one embodiment of the present invention. FIG. 3 schematically illustrates a cross-sectional view of an expansion chamber assembly according to one embodiment of the present invention when it operates in a first mode. FIG. 4 schematically illustrates a cross-sectional view of an expansion chamber assembly according to one embodiment of the present invention when it operates in a second mode. FIG. 5 schematically illustrates details regarding a cam operating module according to one embodiment of the present invention. FIG. 6 schematically illustrates the arrangement of a first bellows member and a second bellows member according to an embodiment of the present invention. Specific details for implementing the invention

[0033] Hereinafter, various embodiments and / or aspects are disclosed with reference to the drawings. For illustrative purposes, numerous specific details are disclosed in the following description to aid in a general understanding of one or more aspects. However, it will also be recognized by those skilled in the art that these aspects may be practiced without such specific details. The following description and the accompanying drawings describe specific exemplary aspects of one or more aspects in detail. However, these aspects are exemplary, and some of the various methods in the principles of the various aspects may be used, and the description is intended to include all such aspects and their equivalents.

[0034] In addition, various aspects and features will be presented by a system that may include multiple devices, components and / or modules, etc. It should also be understood and recognized that various systems may include additional devices, components and / or modules, etc., and / or may not include all of the devices, components, modules, etc. discussed in relation to the drawings.

[0035] As used herein, terms such as "examples," "examples," "aspects," "examples," etc., may not be interpreted as implying that any aspect or design described is better or more advantageous than other aspects or designs.

[0036] Additionally, the terms “comprising” and / or “comprising” should be understood to mean that the relevant feature and / or component is present, but not to exclude the presence or addition of one or more other features, components and / or groups thereof.

[0037] Additionally, terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. Such terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component. The term "and / or" includes a combination of a plurality of related described items or any of a plurality of related described items.

[0038] Furthermore, in the embodiments of the present invention, all terms used herein, including technical or scientific terms, unless otherwise defined, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in the embodiments of the present invention.

[0040] Hereinafter, a centrifugal pump (1) according to one embodiment of the present invention will be described in detail.

[0042] FIG. 1 schematically illustrates a perspective view of a centrifugal pump (1) according to one embodiment of the present invention, and FIG. 2 schematically illustrates an enlarged cross-sectional view of the intermediate housing (8000) side according to one embodiment of the present invention.

[0044] According to one embodiment of the present invention, a centrifugal pump (1) for pumping fluid from a tank of the present invention may include: a shaft (2000) extending into the interior of the tank; a fluid pumping unit (3000) connected to the lower end of the shaft (2000) for transporting fluid contained in the tank; a driving unit (4000) connected to the upper end of the shaft (2000) for providing rotational power to the fluid pumping unit (3000); a fluid discharge unit (5000) for guiding the fluid transported from the tank to the outside; and an expansion chamber assembly (6000) disposed above the fluid discharge unit (5000), forming a fluid passage path along the outer surface of the shaft (2000), and opening and closing the fluid passage path.

[0045] At this time, the expansion chamber assembly (6000) can operate in any one of the following modes: a first mode in which the fluid passage path is opened to allow fluid to move; and a second mode in which the fluid passage path is blocked to prevent fluid from moving.

[0047] The centrifugal pump (1) of the present invention corresponds to a device that sucks in fluid contained in a tank, pressurizes it, and then discharges it to the outside. In one embodiment of the present invention, the centrifugal pump (1) may include a shaft (2000) extending into the inside of the tank, a fluid pumping unit (3000) connected to the lower end of the shaft (2000) to transfer fluid contained in the tank upward, a driving unit (4000) connected to the upper end of the shaft (2000) to provide rotational power to the fluid pumping unit (3000), and a fluid discharge unit (5000) that guides the fluid transferred from the tank to the outside.

[0049] As illustrated in FIG. 1, the shaft (2000) extends in the vertical direction, and its lower end may be accommodated and positioned in the internal space of the tank. The driving unit (4000) may be connected to the upper side of the shaft (2000) and provide rotational power to rotate the shaft (2000).

[0050] The above fluid pumping unit (3000) is housed inside the tank and is connected to the lower end of the shaft (2000) to generate centrifugal force through rotational power transmitted from the shaft (2000). Specifically, the above fluid pumping unit (3000) may include a suction housing (3100) positioned at the very bottom to provide a passage for sucking fluid housed in the tank, and a multi-stage impeller module (3200) positioned to communicate with the suction housing (3100).

[0051] Although not shown in the drawing, each of the multi-stage impeller modules (3200) may include a diffuser housing that guides the flow of fluid and an impeller disposed inside the diffuser housing and coupled to the shaft (2000) to rotate together with the rotation of the shaft (2000). In this configuration, the suction housing (3100) can smoothly suck in the fluid contained in the tank and supply it to the impeller modules (3200), and each of the multi-stage impeller modules (3200) can generate centrifugal force as the shaft (2000) rotates to pressurize the fluid in stages and transport it upward.

[0052] Additionally, as illustrated in FIG. 1, according to one embodiment of the present invention, the centrifugal pump (1) may be provided with a fluid transfer pipe (TP) that is arranged to surround the periphery of the shaft (2000) so as to be received inside the shaft (2000) and is connected to the upper side of the fluid pumping unit (3000) and extends to a penetration (not shown) of the upper flange of the tank. In this configuration, the fluid pressurized upward by the fluid pumping unit (3000) may move upward along the fluid transfer pipe (TP) and then be discharged to the outside of the tank through the penetration of the upper flange (1200) of the tank.

[0053] Meanwhile, the fluid discharge section (5000) is generally connected to the penetration section of the upper flange (1200) of the tank and can be formed in an elbow shape that diverts the fluid radially and guides it to an external pipe.

[0055] The black arrow shown in Fig. 1 schematically illustrates the direction of fluid movement.

[0056] In the configuration of the centrifugal pump (1) of the present invention, when the driving unit (4000) rotates the shaft (2000), the shaft (2000) can transmit rotational power to each impeller of the multi-stage impeller module (3200) of the fluid pumping unit (3000). At this time, the suction housing (3100) of the fluid pumping unit (3000) can guide the fluid stored in the tank to be smoothly sucked into the impeller side, and the impeller can pressurize the fluid by pushing the fluid introduced through the suction housing (3100) radially through rotational motion. In this process, the pressure in the center of the impeller is lowered so that the fluid is continuously sucked in, and the pressure is raised on the outside so that the pressurized fluid can be transported upward. The diffuser housing can guide the fluid through a passage formed inside to regulate the flow of the fluid and increase the pressure.

[0057] The pressurized fluid can travel along the fluid transfer pipe (TP) connected to the upper side of the fluid pumping section (3000) to the upper part of the tank, pass through the penetration of the upper flange, and finally be delivered to the fluid discharge section (5000). The fluid discharge section (5000) is formed in an elbow shape to change the direction of fluid flow and stably discharge fluid into an external piping system.

[0059] Meanwhile, since a motor is connected to the upper side of the fluid discharge section (5000), it is not desirable for a large amount of fluid to leak out. However, during operation, a very small amount of fluid may leak out in the form of liquid or vaporized gas along the outer circumference of the shaft (2000), and such leakage can have the effect of reducing friction in the seal and assisting in cooling. In other words, a sealing member is required that allows a very small amount of fluid to pass through while blocking a large amount of leakage.

[0060] In addition, according to one embodiment of the present invention, it is preferable that the fluid conveyed by the centrifugal pump (1) generally has a liquid form. However, cryogenic liquefied fuels such as liquefied natural gas (LNG), liquefied hydrogen, and liquefied ammonia have low vaporization points and may exist in a gaseous state under ambient temperature conditions; accordingly, a fluid in a gaseous form may coexist at the top of the tank. Furthermore, during operation, a small amount of fluid may rise along the outer circumference of the shaft (2000) and leak into the inner side of the intermediate housing (8000) in a gaseous form. Therefore, it is preferable that the expansion chamber assembly (6000) according to one embodiment of the present invention be designed to effectively control the leakage of fluid in a gaseous form as well as the liquid fluid.

[0062] In conventional centrifugal pump technology, simple static sealing components such as gaskets, packings, and O-rings have generally been employed. However, these simple static sealing components are prone to wear during long-term operation and have limitations in providing sufficient sealing performance, particularly for fluids that are difficult to handle, such as cryogenic fluids or highly volatile liquefied fuels. Most importantly, during maintenance, it is difficult to completely prevent trace amounts of fluid from being exposed to the outside using only these simple static sealing components, which can threaten the safety of operators.

[0064] Accordingly, the present invention discloses an expansion seal assembly (6000) having a dual mode in which, in a first mode for operation, a fluid passage path formed along the outer circumference of a shaft (2000) is opened to allow a small amount of fluid to flow out, thereby preventing unnecessary wear of the sealing member, and in a second mode for maintenance, the fluid passage path is blocked to prevent external leakage of fluid. Due to this configuration, the centrifugal pump (1) of the present invention can maintain the durability and reliability of the pump during operation, while also having the effect of fundamentally blocking safety risks caused by fluid leakage during the maintenance process.

[0066] The specific structure and operating principle of the above-mentioned expansion chamber assembly (6000) will be explained in detail through the embodiments and drawings described later.

[0068] FIGS. 2(a) and FIGS. 2(b) are drawings that respectively show an enlarged view of the indicated B area of ​​FIGS. 1, where FIGS. 2(a) shows a state in which only a bearing module (7000) is placed inside the middle housing (8000), and FIGS. 2(b) shows a state in which only an expansion chamber assembly (6000) is placed inside the middle housing (8000).

[0070] According to one embodiment of the present invention, the centrifugal pump (1) may further include: a bearing module (7000) disposed below the driving unit (4000) and rotatably supporting the shaft (2000); and an intermediate housing (8000) disposed between the driving unit (4000) and the fluid discharge unit (5000) and accommodating the expansion chamber assembly (6000) and the bearing module (7000) as an internal space.

[0072] The above-mentioned intermediate housing (8000) is positioned between the driving unit (4000) and the fluid discharge unit (5000) to form an internal space, accommodates the shaft (2000) inside, and corresponds to a configuration that protects the bearing module (7000) and the expansion chamber assembly (6000).

[0073] As illustrated in FIG. 2(a), a bearing module (7000) may be disposed in the internal space of the intermediate housing (8000) to rotatably support the shaft (2000) located below the driving unit (4000). The bearing module (7000) suppresses shaking or eccentricity that may occur during rotation of the shaft (2000) to maintain a stable rotational state, and by minimizing friction with the shaft (2000), it can reduce power loss and improve the durability of the pump.

[0074] That is, according to one embodiment of the present invention, a bearing module (7000) disposed inside a middle housing (8000) suppresses runout of the shaft (2000), thereby reducing the occurrence of unevenness at the mating surface between the sealing groove (6210) and the sealing protrusion (6310) and preventing uneven wear of the sealing surface.

[0076] In addition, as shown in FIG. 2(b), an expansion assembly (6000) may be disposed in the internal space of the intermediate housing (8000), spaced downward from the bearing module (7000) and arranged along the outer surface of the shaft (2000).

[0078] According to one embodiment of the present invention, the expansion assembly (6000) comprises: a lower flange (6100) that accommodates the shaft (2000) in the center; and an upper flange (6200) that is connected to the lower flange (6100) via a connecting means, is spaced upward, accommodates the shaft (2000) in the center, and is positioned to be movable along the shaft (2000). and a seal housing (6300) that is spaced above the upper flange (6200) and fixed to the shaft (2000); wherein the upper flange (6200) has a sealing groove (6210) formed on its upper surface that is concave downward along the circumferential direction of the shaft (2000), and the seal housing (6300) may have a sealing protrusion (6310) formed that protrudes downward along a shape corresponding to the sealing groove (6210).

[0080] As shown in FIG. 2(b), the expansion chamber assembly (6000) is positioned adjacent to the fluid discharge section (5000) and corresponds to a configuration that determines whether fluid flows out and the path of the fluid flowing upward from the fluid discharge section (5000).

[0082] To this end, the expansion seal assembly (6000) may include a lower flange (6100), an upper flange (6200) which is connected to the lower flange (6100) through a connecting member and is spaced apart in the upward direction, and a seal housing (6300) which is spaced apart above the upper flange (6200) and fixed to the shaft (2000).

[0084] Specifically, as shown in FIG. 2(b), the lower flange (6100) can be fixed to the inner bottom surface of the intermediate housing (8000), has a circular plate shape overall, and a through hole can be formed in the center to receive the shaft (2000) inside.

[0085] The upper flange (6200) may be spaced upward from the lower flange (6100) via a predetermined connecting means, has a circular plate shape, and may have a through hole formed in the center to accommodate the shaft (2000) inside. The upper flange (6200) may be configured to be movable in the vertical direction along the shaft (2000). For example, in one embodiment of the present invention, the upper flange (6200) may be moved in the vertical direction through an actuator such as a cam operating module (6400).

[0086] The seal housing (6300) may be spaced apart and positioned above the upper flange (6200) and may be formed in a cylindrical shape fixed to the outer circumference of the shaft (2000). The lower end of the seal housing (6300) may be positioned to face the upper surface of the upper flange (6200).

[0087] Accordingly, the lower flange (6100) and the upper flange (6200) are each spaced apart from the outer circumference of the shaft (2000) to form a continuous annular space along the outer circumference of the shaft (2000), and also a space can be provided through which fluid can pass by forming a certain gap between the upper surface of the upper flange (6200) and the lower part of the seal housing (6300).

[0089] That is, as shown in FIG. 2(b), the lower flange (6100), upper flange (6200), and seal housing (6300) are spaced apart from each other to form a fluid passage path.

[0090] Specifically, the lower flange (6100) accommodates the shaft (2000) in the center, but is spaced apart from the outer circumference of the shaft (2000), so that an annular space can be formed between the shaft (2000) and the lower flange (6100). This annular space can form part of a fluid passage path through which fluid can pass. Additionally, the upper flange (6200) is connected to the lower flange (6100) via a connecting means, but is also spaced apart from the outer circumference of the shaft (2000), so that an annular space is formed between the shaft (2000) and the upper flange (6200), and this can also form part of a fluid passage path. Furthermore, the upper surface of the upper flange (6200) and the lower portion of the seal housing (6300) are arranged to face each other with a gap between them, so that the space between them can also function as a passage through which fluid can move.

[0091] Accordingly, in one embodiment of the present invention, the fluid discharged from the fluid discharge unit (5000) can move upward along the outer circumference of the shaft (2000), pass through the gap between the lower flange (6100) and the shaft (2000), pass through the gap between the upper flange (6200) and the shaft (2000), and move along the gap between the upper surface of the upper flange (6200) and the lower part of the seal housing (6300). In the present invention, this series of passages is defined as a 'fluid passage path'.

[0092] According to one embodiment of the present invention, the expansion assembly (6000) can achieve the effect of ensuring the alignment of the opening and closing positions and facilitating verification by defining the gap between the lower flange (6100) and the shaft (2000), the gap between the upper flange (6200) and the shaft (2000), and the gap between the upper surface of the upper flange (6200) and the lower part of the seal housing (6300) as fluid passage paths.

[0094] In one embodiment of the present invention, the upper flange (6200) can control whether it contacts the seal housing (6300) by moving up and down along the shaft (2000). That is, when the upper flange (6200) contacts the seal housing (6300), the fluid passage path can be blocked, and when the upper flange (6200) does not contact the seal housing (6300), the fluid passage path can be opened.

[0096] Meanwhile, the upper flange (6200) may be provided with a sealing groove (6210) formed by continuously recessing downward along the circumferential direction of the shaft (2000) on its upper surface. It is preferable that the sealing groove (6210) be formed to have an annular shape when viewed from above.

[0097] Meanwhile, a sealing protrusion (6310) protruding downward along a shape corresponding to the sealing groove (6210) may be provided at the lower end of the sealing housing (6300). The sealing protrusion (6310) may be formed continuously in an annular shape and arranged to coincide with the circumference of the sealing groove (6210).

[0098] That is, it may be preferable for each of the sealing groove (6210) and sealing protrusion (6310) to be positioned on the same radius with respect to the center of the shaft (2000).

[0100] At this time, according to one embodiment of the present invention, when the expansion seal assembly (6000) operates in a first mode, the sealing groove (6210) of the upper flange (6200) and the seal protrusion of the seal housing (6300) are spaced apart from each other and do not come into contact with each other, thereby opening the fluid passage path.

[0101] When the expansion seal assembly (6000) operates in a second mode, the upper flange (6200) can come into contact with the seal housing (6300) by moving upward. At this time, the sealing protrusion (6310) engages with the inner side of the sealing groove (6210), thereby more completely blocking the fluid passage path.

[0103] Specifically, when the expansion seal assembly (6000) operates in the first mode, the upper flange (6200) is in a lower position, and the sealing groove (6210) and the sealing protrusion (6310) can be maintained in a spaced-apart state. Accordingly, a predetermined gap is maintained between the upper surface of the upper flange (6200) and the lower part of the seal housing (6300), and the gap can form a fluid passage path in continuous with the gap between the lower flange (6100) and the shaft (2000) and the gap between the upper flange (6200) and the shaft (2000) described above.

[0104] On the other hand, when the expansion seal assembly (6000) is switched to the second mode, the upper flange (6200) moves upward, and as a result, the sealing protrusion (6310) can be engaged with the inner side of the sealing groove (6210). When engaged, the side of the sealing protrusion (6310) comes into close contact with the inner wall of the sealing groove (6210), and the bottom surface of the sealing protrusion (6310) comes into close contact with the bottom surface of the sealing groove (6210), thereby substantially blocking the gap between the upper surface of the upper flange (6200) and the lower part of the seal housing (6300).

[0106] Meanwhile, although not shown in the drawings, according to one embodiment of the present invention, an auxiliary sealing member (not shown), such as an O-ring or packing, may be further disposed on the inner side of the sealing groove. Such a sealing member (not shown) can further improve the sealing performance during the process in which the sealing protrusion (6310) and the sealing groove (6210) engage, and can perform the role of ensuring stable sealing performance even during long-term repetitive operation.

[0108] Accordingly, in the second mode, even if the fluid flowing out from the fluid discharge section (5000) and moving upward along the outer circumference of the shaft (2000) passes through the gap between the lower flange (6100) and the shaft (2000) and the gap between the upper flange (6200) and the shaft (2000), a portion of the fluid passage path can be closed by the engagement of the sealing groove (6210) and the sealing protrusion (6310) between the upper surface of the upper flange (6200) and the lower part of the seal housing (6300), which is the final section. Accordingly, the fluid passage path is blocked at the top, thereby suppressing upward leakage of the fluid and reliably preventing gaseous fluid exposure during maintenance.

[0110] FIG. 3 schematically illustrates a cross-sectional view in which an expansion chamber assembly (6000) according to one embodiment of the present invention operates in a first mode, and FIG. 4 schematically illustrates a cross-sectional view in which an expansion chamber assembly (6000) according to one embodiment of the present invention operates in a second mode.

[0112] As illustrated in FIG. 3, when the expansion seal assembly (6000) according to one embodiment of the present invention operates in a first mode, the upper flange (6200) is positioned at a relatively lower position. In this state, the sealing groove (6210) formed on the upper surface of the upper flange (6200) and the sealing protrusion (6310) protruding from the lower end of the seal housing (6300) are spaced apart from each other, and an annular space is formed between them. Accordingly, the fluid discharged from the fluid discharge unit (5000) moves upward along the outer circumference of the shaft (2000), passes sequentially through the gap between the lower flange (6100) and the shaft (2000), the gap between the upper flange (6200) and the shaft (2000), and is finally guided to pass through the gap between the upper surface of the upper flange (6200) and the lower end of the seal housing (6300). In this way, in the first mode, the fluid passage path is continuously open, so that a flow is maintained allowing the fluid to move upward.

[0114] Meanwhile, as illustrated in FIG. 4, when the expansion seal assembly (6000) according to one embodiment of the present invention operates in a second mode, the upper flange (6200) moves upward. Accordingly, the sealing protrusion (6310) engages with the inner side of the sealing groove (6210), and the side and bottom surfaces of the sealing protrusion (6310) come into close contact with the inner wall and bottom surface of the sealing groove (6210). As a result, the gap between the upper surface of the upper flange (6200) and the lower part of the seal housing (6300) is substantially blocked, thereby closing the passage through which the fluid moves upward. Therefore, in the second mode, the fluid passage is blocked, preventing the fluid from leaking out, and ensuring safety during the maintenance process.

[0116] FIG. 5 schematically illustrates details regarding a cam operating module (6400) according to one embodiment of the present invention.

[0118] As described above, the expansion seal assembly (6000) may include: a lower flange (6100) that accommodates the shaft (2000) in the center; an upper flange (6200) that is connected to the lower flange (6100) via a connecting means, is spaced upward, accommodates the shaft (2000) in the center, and is positioned to be movable along the shaft (2000); and a seal housing (6300) that is spaced upward from the upper flange (6200) and fixed to the shaft (2000).

[0119] In one embodiment of the present invention, the upper flange (6200) can control whether it contacts the seal housing (6300) by moving up and down along the shaft (2000). That is, when the upper flange (6200) contacts the seal housing (6300), the fluid passage path can be blocked, and when the upper flange (6200) does not contact the seal housing (6300), the fluid passage path can be opened.

[0120] In one embodiment of the present invention, the expansion assembly (6000) may include a cam actuation module (6400) corresponding to a configuration for moving the upper flange (6200) up and down along the shaft (2000).

[0122] According to one embodiment of the present invention, the cam operating module (6400) may include: a rotating rod (6410) extending radially in the shaft (2000); a cam member (6420) connected to an inner end of the rotating rod (6410) and converting the rotational power of the rotating rod (6410) into linear movement power; and a follower rod (6430) having its lower end connected to the cam member (6420) and its upper end connected to the lower end of the upper flange (6200).

[0123] According to one embodiment of the present invention, when the rotary rod (6410) rotates in one direction, the rotational power is converted into linear movement power by the cam member (6420), thereby moving the upper flange (6200) upward along the shaft (2000), so that the expansion chamber assembly (6000) operates in a second mode, and when the rotary rod (6410) rotates in the other direction, the rotational power is converted into linear movement power by the cam member (6420), thereby moving the upper flange (6200) downward along the shaft (2000), so that the expansion chamber assembly (6000) operates in a first mode.

[0125] FIG. 5(a) schematically illustrates a perspective view of a cam operating module (6400) when the expansion chamber assembly (6000) is operating in a first mode, and FIG. 5(b) schematically illustrates a perspective view of a cam operating module (6400) when the expansion chamber assembly (6000) is operating in a second mode.

[0127] The above-mentioned rotary rod (6410) may be a rod member extending radially along the shaft (2000). In this configuration, the rotary rod (6410) may receive rotational power from one end (left end based on FIG. 5(a)) and rotate axially, and the other end may extend in the direction of the shaft (2000) and be coupled with a cam member (6420). Accordingly, rotational power applied from the outside can be transmitted to the internal cam member (6420) through the rotary rod (6410).

[0129] The cam member (6420) is connected to the inner end of the rotating rod (6410) and can perform the function of converting rotational motion into linear motion. Specifically, the cam member (6420) has a cam profile including an inclined surface or a curved surface, thereby converting the rotational motion generated when the rotating rod (6410) rotates into linear motion in the up-and-down direction. Due to this conversion function, the follower rod (6430) can move upward or downward depending on the rotational direction of the rotating rod (6410).

[0131] The lower end of the follower rod (6430) is coupled to the cam member (6420), and the upper end penetrates the lower surface of the middle housing (8000) and is coupled to the lower end of the upper flange (6200), thereby allowing the linear motion of the cam member (6420) to be directly transmitted. Therefore, when the cam member (6420) rotates in a manner that pushes the follower rod (6430) upward, the follower rod (6430) can push the upper flange (6200) upward along the shaft (2000). Similarly, when the cam member (6420) rotates in a manner that lowers the follower rod (6430), the follower rod (6430) can lower the upper flange (6200) downward along the shaft (2000).

[0133] The cam member (6420) may preferably have a teardrop shape. More specifically, the other end of the rotating rod (6410) may be connected to the lower end of the cam member (6420) so that the cam member (6420) rotates together with the rotating rod (6410) when the rod rotates. Additionally, the lower end of the follower rod (6430) may be positioned to contact the outer side of the cam member (6420), and in this case, the outer side of the cam member (6420) acts as a cam profile so that the follower rod (6430) can move up and down according to the rotation angle.

[0135] To facilitate this, a roller member is further provided at the lower end of the follower rod (6430) so that it can stably roll along the curved surface of the cam member (6420) and make contact. Accordingly, the follower rod (6430) slides along the outer surface of the cam member (6420), and as a result, the upper flange (6200) can move stably in the vertical direction.

[0137] The teardrop shape of the cam member (6420) includes an inclined surface on its side that gradually rises, thereby causing the position of the follower rod (6430) to change depending on the rotational position. In particular, when the lower end of the follower rod (6430) is located at the highest side of the cam member (6420), that is, at the top of the teardrop shape, the follower rod (6430) rises to the top. At this time, the upper flange (6200) connected to the follower rod (6430) moves together to the top and can come into contact with the bottom of the seal housing (6300), and as a result, the sealing protrusion (6310) engages with the inner side of the sealing groove (6210). Thus, the fluid passage path is completely blocked, and the operating state of the second mode can be realized.

[0138] For example, in the state of the cam operating part illustrated in FIG. 5(a), when the rotary rod (6410) is rotated clockwise about the central axis, the cam member (6420) is also rotated clockwise, so that the lower end of the follower rod (6430) can move along the side slope of the cam member (6420). Finally, when the lower end of the follower rod (6430) is located at the upper end of the teardrop shape corresponding to the highest side part of the cam member (6420), the follower rod (6430) can rise to the top, and accordingly, the upper flange (6200) also moves to the top and can come into contact with the lower end of the seal housing (6300).

[0140] Conversely, when the lower end of the follower rod (6430) is located on the lower side of the cam member (6420), the follower rod (6430) moves downward, and the upper flange (6200) moves downward on the shaft (2000). At this time, the sealing groove (6210) and the sealing protrusion (6310) are separated from each other and do not come into contact, so a first mode state in which the fluid passage path is opened can be realized.

[0142] That is, the rotary rod (6410), cam member (6420), and follower rod (6430) operate organically with each other to convert the simple rotational power of an external driving source into linear movement of the upper flange (6200), thereby functioning as a key component that enables the expansion chamber assembly (6000) to stably switch between the first mode and the second mode.

[0144] FIG. 6 schematically illustrates the arrangement of a first bellows member (6500) and a second bellows member (6600) according to one embodiment of the present invention.

[0145] (In FIG. 6, the outline of the upper flange (6200) is dotted to clearly illustrate the first bellows member (6500) and the second bellows member (6600).)

[0147] As described above, the expansion assembly (6000) may include a lower flange (6100) that accommodates the shaft (2000) in the center; and an upper flange (6200) that is spaced above the lower flange (6100), accommodates the shaft (2000) in the center, and is positioned to be movable along the shaft (2000).

[0148] At this time, according to one embodiment of the present invention, the expansion assembly (6000) may further include: a first bellows member (6500) having a first diameter, with its lower end fixed to the lower flange (6100) and its upper end fixed to the upper flange (6200); and a second bellows member (6600) having a second diameter larger than the first diameter, with its lower end fixed to the lower flange (6100) and its upper end fixed to the upper flange (6200). The first bellows member (6500) and the second bellows member (6600) may be concentrically arranged around the shaft (2000) and spaced apart from each other along the radial direction.

[0150] In this configuration, the first bellows member (6500) and the second bellows member (6600) each have their upper and lower ends welded to the lower flange (6100) and the upper flange (6200), respectively, thereby forming a sealing space between the first bellows member (6500) and the second bellows member (6600). When the upper flange (6200) moves upward along the shaft (2000), the volume of the sealing space expands, thereby lowering the pressure in the sealing space and preventing the fluid from leaking out of the fluid passage path.

[0152] In one embodiment of the present invention, the expansion assembly (6000) may include a first bellows member (6500) and a second bellows member (6600) as a connecting means for connecting the lower flange (6100) and the upper flange (6200) to each other.

[0153] The first bellows member (6500) may have a corrugated corrugated structure formed by forming a plurality of peaks and valleys on its outer surface, and may have a hollow tube shape with flanges formed at the top and bottom. In this configuration, the first bellows member (6500) may have its bottom end fixed to the lower flange (6100) and its top end fixed to the upper flange (6200), and may have a relatively narrow diameter centered on the shaft (2000).

[0154] Meanwhile, the second bellows member (6600) may have a corrugated corrugated structure formed by forming multiple peaks and valleys on its outer surface, similar to the first bellows member (6500), and may have a hollow tube shape with flanges formed at the top and bottom. In this configuration, the second bellows member (6600) may have its bottom fixed to the lower flange (6100) and its top fixed to the upper flange (6200), and may be positioned around the shaft (2000) and have a larger diameter than the first bellows member (6500).

[0156] That is, the first bellows member (6500) and the second bellows member (6600) are arranged concentrically around the shaft (2000), and a sealed space (A) spaced apart along the radial direction may be formed between them. The sealed space (A) may have a completely sealed structure by welding and fixing the upper and lower ends of both bellows members (6500, 6600) to the lower flange (6100) and the upper flange (6200), respectively.

[0158] For example, by referring to FIGS. 3 and FIGS. 4 together, the sealing space pressure (P1) when the expansion chamber assembly (6000) operates in the first mode and the sealing space pressure (P2) when the expansion chamber assembly (6000) operates in the second mode can be compared. At this time, as the pressure at P2 is maintained relatively higher than at P1, the sealing space functions as a pressure blocking layer in the second mode. Accordingly, the path through which the fluid moves upward along the outer circumference of the shaft (2000) is completely blocked at the lower end of the seal housing (6300) and the upper end of the upper flange (6200), thereby preventing the fluid from passing through that section. Furthermore, this blocking structure can fundamentally suppress the fluid from bypassing or leaking in other lateral or radial directions, so that the sealing performance of the expansion chamber assembly (6000) can be more reliably improved.

[0160] In addition, since the bellows member (6500, 6600) of the present invention has axial elasticity, it can operate stably without damage or wear even if the upper flange (6200) moves repeatedly in the up and down direction. Accordingly, long-term durability can be secured during the first mode switching process of the expansion chamber assembly (6000), and the effect of completely blocking fluid leakage in the second mode can be achieved.

[0162] According to one embodiment of the present invention, the expansion seal assembly minimizes friction and surface pressure caused by contact in a first mode and implements sealing only in a second mode, thereby fundamentally reducing the continuous contact section with a high contribution to wear, which can have the effect of increasing the lifespan of the shaft support system.

[0163] According to one embodiment of the present invention, by structurally blocking the fluid passage path in the second mode, the exposure of vaporized fluid to a hazardous environment is completely blocked, thereby enabling the effect of reducing worker safety and environmental leakage risks.

[0164] According to one embodiment of the present invention, the centrifugal pump is applicable to ambient temperature volatile chemicals including vaporizable low-viscosity fluids such as cryogenic LNG, liquid hydrogen, and liquid ammonia, thereby enabling excellent scalability to various facilities such as chemical plants and vessels for liquid fuel.

[0165] According to one embodiment of the present invention, the sealing groove of the upper flange and the sealing protrusion of the seal housing are configured to engage in an annular manner, thereby enabling uniform sealing in all circumferential directions and ensuring stable sealing performance even under eccentricity or local pressure.

[0166] According to one embodiment of the present invention, by having a cam member with a teardrop shape and a roller member disposed at the bottom of a follower rod, linear motion with low friction can be achieved along the cam profile, thereby enhancing the precision and reproducibility of the vertical position control of the upper flange.

[0167] According to one embodiment of the present invention, a first bellows member and a second bellows member are arranged concentrically to form a sealing space between them, and when the upper flange moves upward, the volume of the sealing space expands and the pressure decreases, thereby preventing the fluid from flowing out of the fluid passage path.

[0168] According to one embodiment of the present invention, a bearing module disposed inside a middle housing suppresses runout of the shaft, thereby reducing the occurrence of misalignment at the mating surface between the sealing groove and the sealing protrusion, and can exhibit the effect of preventing uneven wear of the sealing surface.

[0169] According to one embodiment of the present invention, by configuring the system to switch between a first mode and a second mode by operating a rotary rod from the outside, the stopping and maintenance procedures of the pump can be simplified and the turnaround time can be shortened.

[0171] Although the embodiments have been described above with reference to limited examples and drawings, those skilled in the art can make various modifications and variations from the description above. For example, suitable results may be achieved even if the described techniques are performed in a different order than described, and / or if the components of the described system, structure, device, circuit, etc. are combined or assembled in a form different from described, or replaced or substituted by other components or equivalents. Therefore, other implementations, other embodiments, and equivalents to the claims below are also within the scope of the claims. Explanation of the symbols

[0173] 1: Centrifugal pump 1000: Tank 1100: Tank body 1200: Top flange of the tank 2000: Shaft 3000: Fluid pumping unit 3100: Suction housing 3200: Impeller Module 4000: Drive Unit 5000: Fluid discharge section 6000: Expansion chamber assembly 6100: Lower flange 6200: Upper flange 6210: Ceiling Groove 6300: Seal Housing 6310: Sealing protrusion 6400: Cam actuation module 6410: Rotating rod 6420: Cam member 6430: Follower load 7000: Bearing module 8000: Intermediate housing TP: Transfer pipe A: Sealed space

Claims

Claim 1 A centrifugal pump for pumping fluid from a tank, comprising: a shaft extending into the interior of the tank; a fluid pumping unit connected to the lower end of the shaft to transfer fluid contained in the tank; a driving unit connected to the upper end of the shaft to provide rotational power to the fluid pumping unit; a fluid discharge unit guiding the fluid transferred from the tank to the outside; and an expansion chamber assembly disposed above the fluid discharge unit, forming a fluid passage path along the outer surface of the shaft, and opening and closing the fluid passage path; wherein the expansion chamber assembly operates in any one of the following modes: a first mode for operation in which the fluid passage path is opened to allow fluid to move; and a second mode for maintenance in which the fluid passage path is blocked to prevent fluid from moving, thereby preventing fluid from leaking out along the outer surface of the shaft. Claim 2 A centrifugal pump according to claim 1, wherein the centrifugal pump further comprises: a bearing module disposed below the driving unit and rotatably supporting the shaft; and an intermediate housing disposed between the driving unit and the fluid discharge unit and accommodating the expansion chamber assembly and the bearing module in an internal space. Claim 3 A centrifugal pump according to claim 1, wherein the expansion seal assembly comprises: a lower flange that receives the shaft in the center; an upper flange that is connected to the lower flange via a connecting means, is spaced upward, receives the shaft in the center, and is positioned to be movable along the shaft; and a seal housing that is spaced upward from the upper flange and fixed to the shaft; wherein the upper flange has a sealing groove formed on its upper surface that is concave downward along the circumferential direction of the shaft, and the seal housing has a sealing protrusion formed that protrudes downward along a shape corresponding to the sealing groove. Claim 4 A centrifugal pump according to claim 3, wherein when the expansion seal assembly operates in a first mode, the sealing groove of the upper flange and the seal protrusion of the seal housing are spaced apart from each other to open a fluid passage path, and when the expansion seal assembly operates in a second mode, the sealing protrusion engages with the inner side of the sealing groove to block the fluid passage path. Claim 5 A centrifugal pump according to claim 1, wherein the expansion seal assembly comprises: a lower flange that receives the shaft in the center; an upper flange that is connected to the lower flange via a connecting means, is spaced upward, receives the shaft in the center, and is positioned to be movable along the shaft; a seal housing that is spaced upward from the upper flange and fixed to the shaft; and a cam operating module that moves the upper flange in the up-and-down direction along the shaft; wherein the cam operating module comprises: a rotary rod extended in the radial direction of the shaft; a cam member connected to the inner end of the rotary rod and converting the rotational power of the rotary rod into linear movement power; and a follower rod, the lower end of which is connected to the cam member and the upper end of which is connected to the lower end of the upper flange. Claim 6 A centrifugal pump according to claim 5, wherein when the rotary rod rotates in one direction, the rotational power is converted into linear movement power by the cam member, thereby moving the upper flange upward along the shaft, so that the expansion chamber assembly operates in a second mode, and when the rotary rod rotates in the other direction, the rotational power is converted into linear movement power by the cam member, thereby moving the upper flange downward along the shaft, so that the expansion chamber assembly operates in a first mode. Claim 7 A centrifugal pump according to claim 1, wherein the expansion assembly comprises: a lower flange that receives the shaft in the center; an upper flange that is spaced above the lower flange and receives the shaft in the center and is movably disposed along the shaft; a first bellows member having a first diameter, with its lower end fixed to the lower flange and its upper end fixed to the upper flange; and a second bellows member having a second diameter larger than the first diameter, with its lower end fixed to the lower flange and its upper end fixed to the upper flange; wherein the first bellows member and the second bellows member are concentrically arranged around the shaft and spaced apart from each other along the radial direction. Claim 8 A centrifugal pump according to claim 7, wherein the upper and lower ends of the first bellows member and the second bellows member are respectively welded to the lower flange and the upper flange to form a sealing space between the first bellows member and the second bellows member, and when the upper flange moves upward along the shaft, the volume of the sealing space expands and the pressure in the sealing space decreases, thereby preventing the fluid from flowing out of the fluid passage path.

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