Two-shaft, two-speed transverse centrifugal pump

Abstract

This two-shaft, two-speed transverse centrifugal pump comprises: a suction impeller that is positioned in a duct casing and suctions a fluid through a suction port; a hollow rotary shaft rotating the suction impeller at a first rotational speed; a volute casing including a discharge port for discharging the fluid; a discharge impeller that is positioned in the volute casing and discharges the fluid through the discharge port in a direction perpendicular to the hollow rotary shaft; and a solid rotary shaft that rotates the discharge impeller at a second rotational speed higher than the first rotational speed, has the same axial center as the hollow rotary shaft, and is inserted into the hollow rotary shaft.

Description

2-axis 2-speed horizontal centrifugal pump

[0001] The present invention relates to a two-axis, two-speed horizontal centrifugal pump, and more specifically, to a two-axis, two-speed horizontal centrifugal pump that can achieve high head and high flow rate despite being compact and simple in structure by having two coaxial rotating shafts with different rotational speeds, whereby a suction-side impeller sucks fluid at a low speed and a discharge-side impeller discharges fluid at a high speed.

[0002] Typically, a centrifugal pump is a pump that sucks in and discharges fluid through centrifugal force. It is configured with an impeller driven by a power source that sucks in fluid toward the center and discharges it toward the periphery. Since a centrifugal pump with a single impeller has limited head, a multistage centrifugal pump has been disclosed that stacks multiple impellers on a single shaft to achieve high head (see Patent No. 10-1647421).

[0003] However, these multi-stage centrifugal pumps have installation limitations due to the overall length being increased by stacking impellers, and the efficiency of the pump is reduced due to the addition of the pump casing, and the packing method and quantity of various sealing parts are increased due to the increase in pressure, which also increases the axial load applied to the pump shaft, providing a negative cause in terms of the shaft power of the pump, and also increasing the possibility of fluid leakage.

[0004] In addition, in the case of pumps for indoor fire hydrant pressurization devices, although the purpose of initial fire suppression should be achieved through normal pump operation in an emergency, there are frequent cases where problems arise in the normal functioning of the pump in an emergency because basic preventive maintenance of the pump is not carried out smoothly, and thus the need for an intelligent self-diagnosis function that can easily diagnose basic pump maintenance items is emerging.

[0005] To solve these problems, there is a growing need for a two-axis, two-speed horizontal centrifugal pump that is not a multi-stage pump type, minimizes fluid leakage, and has a self-diagnosis function.

[0006] The problem to be solved by the present invention is to provide a two-shaft, two-speed horizontal centrifugal pump that can achieve high head and high flow rate while being compact and having a simple structure, by having two rotating shafts with different rotational speeds on the same axis so that the suction-side impeller sucks fluid at a low speed and the discharge-side impeller discharges fluid at a high speed.

[0007] The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0008] According to one embodiment of the present invention for solving the above problem, a two-axis two-speed horizontal centrifugal pump includes a suction impeller positioned in a duct casing and sucking fluid through a suction port, a hollow rotational shaft rotating the suction impeller at a first rotational speed, a volute casing including a discharge port for discharging fluid, a discharge impeller positioned in the volute casing and discharging fluid through the discharge port in a direction perpendicular to the hollow rotational shaft, and a solid rotational shaft rotating the discharge impeller at a second rotational speed higher than the first rotational speed and having the same axial center as the hollow rotational shaft and inserted into the hollow rotational shaft.

[0009] According to the present invention, a two-shaft, two-speed horizontal centrifugal pump capable of achieving high head and high flow rate while being compact and having a simple structure can be provided by having two rotating shafts having different rotational speeds on the same axis, so that a suction-side impeller sucks fluid at a low speed and a discharge-side impeller discharges fluid at a high speed.

[0010] In addition, a two-axis, two-speed horizontal centrifugal pump can be provided that has a shaft sealing pressure reducing structure to minimize fluid leakage, simplify the existing packing structure, and reduce the load applied to the rotating shaft by the existing packing structure.

[0011] In addition, a two-axis, two-speed horizontal centrifugal pump with a self-diagnosis function that continuously diagnoses the pump can be provided, by having an optical level sensor (or, electrode rod when in contact) for checking the level of the fluid contained inside the pump and an RPM sensor for measuring the rotational speed of the rotating shaft for an intelligent self-diagnosis function of the pump.

[0012] FIG. 1 is a simplified perspective view of a two-axis, two-speed horizontal centrifugal pump according to one embodiment of the present invention.

[0013] FIG. 2 is a side view of a two-axis, two-speed horizontal centrifugal pump according to one embodiment of the present invention.

[0014] Figure 3 is a cross-sectional view of a two-axis, two-speed horizontal centrifugal pump according to one embodiment of the present invention.

[0015] FIG. 4 is a cross-sectional view of a type of axial seal pressure relief structure according to one embodiment of the present invention.

[0016] A two-axis, two-speed horizontal centrifugal pump according to one embodiment of the present invention includes a suction impeller positioned within a duct casing and sucking fluid through a suction port, a hollow rotational shaft rotating the suction impeller at a first rotational speed, a volute casing including a discharge port for discharging fluid, a discharge impeller positioned within the volute casing and discharging fluid through the discharge port in a direction perpendicular to the hollow rotational shaft, and a solid rotational shaft rotating the discharge impeller at a second rotational speed higher than the first rotational speed and having the same axial center as the hollow rotational shaft and inserted into the hollow rotational shaft.

[0017] The present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform a person having ordinary skill in the art to which the present invention pertains of the scope of the invention.

[0018] In this specification, the singular includes the plural unless the context specifically dictates otherwise. As used herein, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, or operations.

[0019] Referring to FIGS. 1 to 4, a two-axis two-speed horizontal centrifugal pump according to one embodiment of the present invention will be described. FIG. 1 is a simplified perspective view of a two-axis two-speed horizontal centrifugal pump according to one embodiment of the present invention. FIG. 2 is a side view of a two-axis two-speed horizontal centrifugal pump according to one embodiment of the present invention.

[0020] Fig. 3 is a cross-sectional view of a two-axis, two-speed horizontal centrifugal pump according to one embodiment of the present invention. Fig. 4 is a cross-sectional view of a type of shaft seal pressure reduction structure according to one embodiment of the present invention.

[0021] Referring to FIGS. 1 to 4, a two-axis, two-speed horizontal centrifugal pump (10) according to one embodiment of the present invention may include a duct casing (20), a suction impeller (30), a hollow rotary shaft (80), a diffuser casing (60), a diffuser (70), a volute casing (40), a discharge impeller (50), a solid rotary shaft (90), a mechanical seal (130), a gland packing, a shaft sealing pressure reducing structure (120), and a self-diagnosis structure.

[0022] The duct casing (20) is a casing that accommodates a suction impeller (30) described later, and may include a suction port (15) through which fluid is sucked.

[0023] The suction impeller (30) is a member that is located within the duct casing (20) and sucks fluid through the suction port (15).

[0024] The hollow rotary shaft (80) is a member that rotates the suction impeller (30) at the first rotation speed.

[0025] The hollow rotation shaft (80) can rotate at a first rotation speed by the power provided by the power source, and accordingly, the suction impeller (30) coupled to the hollow rotation shaft (80) can also rotate at the first rotation speed.

[0026] As the suction impeller (30) rotates by the hollow rotating shaft (80), external fluid can be introduced into the duct casing (20).

[0027] The diffuser casing (60) is a casing that is located between the duct casing (20) and the volute casing (40) described later and accommodates the diffuser (70) described later.

[0028] An O-ring (170) may be interposed between the diffuser casing (60) and the duct casing (20), and an O-ring (170) may also be interposed between the diffuser casing (60) and the volute casing to prevent leakage of the sucked fluid.

[0029] The diffuser (70) can be installed between the suction impeller (30) and the discharge impeller (50), and is an impeller that performs the function of maintaining a static pressure on the fluid before the fluid introduced through the suction impeller (30) flows to the discharge impeller (50).

[0030] The volute casing (40) is a casing that includes a discharge port (25) for discharging the sucked fluid while accommodating a discharge impeller (50).

[0031] The discharge impeller (50) is an impeller that is located within the volute casing (40) and discharges fluid in a direction perpendicular to the hollow rotation axis (80) through the discharge port (25).

[0032] That is, the suction impeller (30) can introduce fluid into the duct casing (20) through the suction port (15), and the introduced fluid can flow into the volute casing (40) through the diffuser (70), and the discharge impeller (50) can discharge the flowed fluid to the outside through the discharge port (25).

[0033] Meanwhile, a wear ring (160) may be interposed between the fitting position where the discharge impeller (50) is fitted in the volute casing (40) and the protrusion of the discharge impeller (50) forming the central through hole, and this wear ring (160) may play a role in adjusting the clearance between the fitting position and the protrusion.

[0034] The solid rotation shaft (90) is a member that rotates the discharge impeller (50) at the second rotation speed.

[0035] The solid rotation shaft (90) can rotate at the second rotation speed by the power provided by the power source, and accordingly, the discharge impeller (50) coupled to the solid rotation shaft (90) can also rotate at the second rotation speed.

[0036] As the discharge impeller (50) rotates by the solid rotation shaft (90), the introduced fluid can be discharged to the outside from the volute casing (40).

[0037] At this time, the second rotation speed of the discharge impeller (50) may be higher than the first rotation speed of the suction impeller (30). That is, the second rotation speed may be relatively high, and the first rotation speed may be relatively low to medium.

[0038] In addition, the solid rotation shaft (90) can be installed by being inserted into the hollow of the hollow rotation shaft (80), and accordingly, the solid rotation shaft (90) and the hollow rotation shaft (80) can have the same axis center (i.e., coaxial).

[0039] In the case of a conventional pump having a single shaft with a single rotation speed, a multi-stage type pump with multiple impellers installed on one shaft was used for high head or high flow rate.

[0040] However, these multistage pumps inevitably become longer and more complex, resulting in space constraints for installation and maintenance difficulties. Furthermore, the additional housing or casing required to form the multistage configuration increases manufacturing costs and complicates manufacturing.

[0041] Considering these problems, the present invention may have two coaxial rotating shafts having different rotational speeds rather than a single rotational speed, and the suction impeller (30) and the discharge impeller (50) may rotate at different rotational speeds by these two rotating shafts, thereby realizing high head and high flow rate.

[0042] In other words, the two-axis, two-speed horizontal centrifugal pump (10) of the present invention can exhibit high head and high flow performance without adopting a multi-stage form with an extended length, and furthermore, while realizing such performance, the pump is miniaturized and its structure is simplified.

[0043] Additionally, conventionally, the suction and discharge ports had various diameters, such as 100 mm, 125 mm, and 150 mm, depending on the required flow rate and head, and various castings and casings had to be manufactured accordingly.

[0044] On the other hand, the present invention is designed so that the suction port and the discharge port can respond with the same diameter (e.g., a single diameter of 100 mm) even if various heads and flow rates are required, thereby achieving standardization and specification unification of products that satisfy various pump specifications of existing pumps with only one cast casing.

[0045] Meanwhile, the solid rotation shaft (90) can be formed by extending to a bearing housing (110) located at the front of the pump (10), and can rotate while being supported by a bearing (100) within the bearing housing (110).

[0046] A mechanical seal (130) is a member that is interposed between a hollow rotating shaft (80) and a solid rotating shaft (90) to form a seal.

[0047] In the case of the present invention, since the solid rotation shaft (90) is installed by being inserted into the hollow of the hollow rotation shaft (80), a space may be formed between the inner surface of the hollow rotation shaft (80) and the outer surface of the solid rotation shaft (90), and accordingly, fluid may leak through this space.

[0048] Taking this into consideration, this leakage problem can be solved by interposing a mechanical seal (130) between the hollow rotation shaft (80) and the solid rotation shaft (90).

[0049] Meanwhile, the mechanical seal (130) is a mechanical device that mechanically changes the gland packing in terms of sealing, and divides the frictional heat between the shaft and the gland packing into the rotary part and stationary part of the mechanical seal (130) to perform sealing through the friction of the two parts.

[0050] Grand packing is a packing that blocks water from flowing into and out of a two-axis, two-speed horizontal centrifugal pump (10).

[0051] These grand packings may include a leading grand packing (140) and a trailing grand packing (220).

[0052] The front end gland packing (140) can be installed around the solid rotating shaft (90) at the front end (or, in front of the volute casing (40)) of a two-axis, two-speed horizontal centrifugal pump (10) to form a seal, and at this time, a front end gland (150) that acts as a stopper can be installed together.

[0053] That is, the front grand packing (140) can be installed between the front inner surface of a two-axis two-speed horizontal centrifugal pump (10) and the solid rotating shaft (90).

[0054] The rear end gland packing (220) can be installed around the hollow rotating shaft (80) at the rear end of the pump (10) (or, the rear of the duct casing (20)) to form a seal, and at this time, a rear end gland (230) that acts as a plug can be installed together.

[0055] That is, the rear grand packing (220) can be installed between the rear inner surface of the pump (10) and the hollow rotary shaft (80).

[0056] The shaft seal pressure relief structure (120) is a structure that reduces the pressure of the shaft seal within a two-shaft, two-speed horizontal centrifugal pump (10) to minimize fluid leakage.

[0057] The two-axis, two-speed horizontal centrifugal pump (10) of the present invention requires a high head, so the internal pressure is high, and accordingly, leakage problems are likely to occur.

[0058] Considering these points, the present invention may include a shaft seal pressure reducing structure (120) to reduce the pressure of the shaft seal device housed inside a two-axis two-speed horizontal centrifugal pump (10).

[0059] This shaft seal pressure relief structure (120) is installed in front of the rear end grand packing (220) to reduce the hydraulic pressure applied to the rear end grand packing (220), thereby reducing the assembly quantity of the rear end grand packing (220).

[0060] In addition, as the number of rear grand packings (220) decreases, the axial load acting on the hollow rotary shaft (80) decreases, which also helps improve the efficiency of the pump.

[0061] To this end, as illustrated in FIG. 4, the axial seal pressure relief structure (120) in one form may include a first pressure relief member (260) and a pressure relief groove structure (300).

[0062] The first pressure-sensitive member (260) may be formed around the hollow rotation shaft (80) and may have a stepped shape. At this time, the method by which the first pressure-sensitive member (260) is formed on the hollow rotation shaft (80) may include a method of press-fitting the hollow rotation shaft (80) by heat shrinkage, but there is no limitation on the method.

[0063] The pressure relief groove structure (300) can be formed facing the first pressure relief member (260) on the inner surface of the two-axis two-speed horizontal centrifugal pump (10) in front of the rear grand packing (220), and can include a plurality of groove portions (290) positioned in parallel with each other.

[0064] Additionally, in the plurality of grooves (290), the distance (height of the gap) between each of the plurality of walls (280) forming the boundary of the adjacent grooves (290) and the first pressure reducing member (260) may all be the same.

[0065] Under this structure, the pressure of the fluid inside the pump (10) decreases as it comes into contact with the inner surface (270) of the groove (290), and the pressure of the fluid can decrease again by Bernoulli's principle as it passes through the narrow gap formed by the wall (280) of the groove (290) that acts as an orifice and the first pressure reducing member (260).

[0066] That is, the fluid firstly forms a constant pressure as it passes through the narrow space formed by the hollow rotating shaft (80), and secondly, the pressure of the fluid with the constant pressure is lowered as it comes into contact with the inner surface (270) of the groove portion (290) of the groove member, and the pressure can be lowered once again as it passes through the narrow gap formed by the wall (280) of the groove portion (290) and the first pressure reducing member (260).

[0067] Through this process, the pressure of the fluid can be lowered, and accordingly, the pressure applied by the fluid to the rear grand packing (220) can be lowered, thereby minimizing fluid leakage and substantially reducing the number of final grand packings, thereby lowering the axial load applied to the hollow rotary shaft (80).

[0068] The self-diagnosis structure is a structure that diagnoses whether there is a leak in the fluid inside the pump (10) or whether the rotating shaft is rotating normally.

[0069] In particular, among the uses of pumps, the pump, which is currently an indoor fire hydrant pressurization device, functions as a kind of insurance product that is intended for use in emergencies (when a fire occurs). Therefore, regular inspections to check for normal operation in preparation for emergencies are not separately regulated by the Fire Service Act and are recommendations, so regular inspections are generally not performed.

[0070] Considering this reality, the present invention enables the pump to perform routine inspections through regular self-diagnosis to determine whether there is an initial abnormality in the pump by providing a self-diagnosis structure.

[0071] For this purpose, the self-diagnosis structure includes an optical level sensor (190) (or electrode rod), a first RPM sensor (200) and a second RPM sensor (210).

[0072] The optical level sensor (190) is a sensor installed in the duct casing (20) to detect fluid leakage.

[0073] In normal condition, no leakage occurs in the pump (10), so the duct casing (20) may be full of fluid, and accordingly, the optical level sensor (190) may not generate a signal.

[0074] Conversely, if a leak occurs due to a crack in the pump casing (frozen in winter or material defect) or a sealing defect in the pump (10), a fluid-free empty space may be formed within the duct casing (20), and accordingly, the optical level sensor (190) may generate a signal to notify the manager that a leak has occurred in the pump (10).

[0075] The first RPM sensor (200) is a sensor that detects whether the hollow rotation shaft (80) is rotated abnormally.

[0076] Specifically, the first RPM sensor (200) measures the rotational speed of the hollow rotational shaft (80) and compares it with the rotational speed of the hollow rotational shaft (80) in a normal state. If the measured rotational speed is out of the preset normal range, the first RPM sensor (200) notifies the manager of this fact so that the manager can inspect the pump (10).

[0077] The second RPM sensor (210) is a sensor that detects whether the rotation of the solid rotation shaft (90) is abnormal.

[0078] Specifically, the second RPM sensor (210) measures the rotational speed of the solid rotation shaft (90) and compares it with the rotational speed of the solid rotation shaft (90) in a normal state. If the measured rotational speed is out of the preset normal range, the second RPM sensor (210) notifies the manager of this fact so that the manager can inspect the pump (10).

[0079] In this regard, when abnormal rotation occurs in the rotating shaft, if the pump is not operated for a long time, water stagnant inside the casing may cause rust, scale, and algae to accumulate in the gap between the impeller and the rear of the casing, which may cause a blockage phenomenon, and as a result, the rotation of the rotating shaft may slow down, causing abnormal rotation.

[0080] Alternatively, if a problem such as damage occurs in the bearing or seal in contact with the rotating shaft, the rotation of the rotating shaft may slow down and cause rotation abnormalities.

[0081] That is, the first RPM sensor (200) and the second RPM sensor (210) measure the rotational speed of the hollow rotation shaft (80) or the solid rotation shaft (90) to detect whether there is an abnormality in the rotation of the pump (10) and notify the manager of this, thereby facilitating management of the pump (10).

[0082] Additionally, a two-axis two-speed horizontal centrifugal pump (10) according to one embodiment of the present invention may further include a flywheel (250) and a driving drive (240).

[0083] The flywheel (250) is a member that transmits power provided by a single power source to the driving drive (240) described later.

[0084] At this time, the power source may be, but is not limited to, an engine or an electric motor.

[0085] The driving drive (240) is a member located between the flywheel (250) and the hollow rotation shaft (80) and the solid rotation shaft (90), and transmits the power received from the flywheel (250) to the hollow rotation shaft (80) and the solid rotation shaft (90).

[0086] This driving drive (240) is a type of planetary reducer and may include a ring gear, a planetary gear, and a sun gear.

[0087] By using a planetary reducer as the driving drive (240), even if a single power source is used, the hollow rotation shaft (80) and the solid rotation shaft (90) can be coaxial and have different rotation speeds.

[0088] That is, by using a planetary reducer, the hollow rotation shaft (80) and the solid rotation shaft (90) can be driven at different rotation speeds with a single power source, and the structure can also be simplified.

[0089] In addition, when using an engine as a power source, while conventional single-axis and single-rotation speed pumps require a high-output engine, the present invention can drive a hollow rotation shaft (80) and a solid rotation shaft (90) at different rotation speeds through a planetary reducer by simply operating the engine's speed change lever (typically an accelerator cable) even when using a conventional engine.

[0090] Therefore, there is no need to use expensive high-power engines or expensive inverter motors.

[0091] Although the embodiments of the present invention have been described with reference to the attached drawings, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without altering the technical concept or essential features thereof. Therefore, the embodiments described above should be understood to be illustrative in all respects and not restrictive.

[0092] The description of the symbol is as follows:

[0093] 10: 2-shaft 2-speed horizontal centrifugal pump 15: Suction port

[0094] 20: Duct casing 25: Outlet

[0095] 30: Suction impeller 40: Volute casing

[0096] 50: Discharge impeller 60: Diffuser casing

[0097] 70: Diffuser 80: Hollow rotating shaft

[0098] 90: Solid rotation axis 100: Bearing

[0099] 110: Bearing housing 120: Shaft seal pressure relief structure

[0100] 130: Mechanical seal 140: Fleet gland packing

[0101] 150: Fleet Grand 160: Wear Ring

[0102] 170: O-ring 180: Fastening bolt

[0103] 190: Optical level sensor 200: 1st RPM sensor

[0104] 210: Second RPM sensor 220: Rear gland packing

[0105] 230: Rear Grand 240: Drive Drive

[0106] 250: Flywheel 260: First damping member

[0107] 270: Inside 280: Wall

[0108] 290: Home 300: Decompression home structure

[0109] The present invention relates to a two-shaft, two-speed horizontal centrifugal pump that can achieve high head and high flow rate despite being compact and simple in structure by having two rotating shafts with different rotational speeds on the same axis so that a suction-side impeller sucks fluid at a low speed and a discharge-side impeller discharges fluid at a high speed, and thus has industrial applicability.

Claims

1. Duct casing including an inlet through which fluid is sucked; A suction impeller positioned within the duct casing and sucking the fluid through the suction port; A hollow rotating shaft that rotates the above suction impeller at a first rotational speed; A volute casing including a discharge port for discharging the fluid; A discharge impeller positioned within the volute casing and discharging the fluid through the discharge port in a direction perpendicular to the hollow rotation axis; and A two-shaft, two-speed horizontal centrifugal pump that rotates the discharge impeller at a second rotational speed higher than the first rotational speed and includes a solid rotational shaft inserted into the hollow rotational shaft while having the same axial center as the hollow rotational shaft.

2. In paragraph 1, A two-shaft, two-speed horizontal centrifugal pump further comprising a mechanical seal interposed between the hollow rotating shaft and the solid rotating shaft to form a seal.

3. In paragraph 1, A rear gland packing installed around the hollow rotary shaft at the rear of the duct casing to form a seal; and A two-shaft, two-speed horizontal centrifugal pump further comprising an axial seal pressure reducing structure installed in front of the rear-end grand packing to reduce the pressure of the axial seal fluid applied to the rear-end grand packing.

4. In paragraph 3, The above-mentioned shaft seal pressure relief structure is, A first pressure reducing member formed around the hollow rotating shaft and having a stepped shape; and A pressure reducing groove structure including a plurality of grooves positioned in parallel and formed facing the first pressure reducing member on the inner surface of a two-axis two-speed horizontal centrifugal pump in front of the rear grand packing, A two-axis, two-speed horizontal centrifugal pump, wherein the distance between each of the plurality of walls forming the boundary of the adjacent grooves and the first pressure reducing member is the same.

5. In paragraph 1, A two-axis, two-speed horizontal centrifugal pump further comprising a diffuser installed between the suction impeller and the discharge impeller.

6. In paragraph 1, A two-axis, two-speed horizontal centrifugal pump further comprising an optical level sensor installed in the above duct casing to detect leakage of the fluid.

7. In paragraph 1, A first RPM sensor that detects whether the hollow rotating shaft is rotated abnormally; and A two-axis, two-speed horizontal centrifugal pump further comprising a second RPM sensor for detecting whether the solid rotating shaft is rotated abnormally.

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