Vortex prevention device and pump device

Abstract

To save the space of pump equipment while taking measures to prevent a vortex of suction piping.SOLUTION: A pump device includes a plurality of pump units for transferring water from a suction inflow part to a delivery water tank, and a vortex breaker attached to the pump unit. The pump unit includes a suction pipe partially arranged in the suction inflow part, a pump part connected with the suction pipe, and a driving source for driving the pump part. The adjacent two pump units are arranged in such a manner as the corresponding two suction pipes form a predetermined angle. The vortex breaker includes a horizontal vortex breaking plate disposed in a radial outer side of a suction port of the suction pipe and extending almost horizontally from the suction port of the plurality of pump units, and a splitter provided in the lower side of the suction port of the suction pipe. Thus, generation of an air suction vortex and an underwater vortex in the suction inflow part can be prevented.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vortex prevention device used in a pump device for pumping up drainage such as rainwater, and a pump device equipped with this vortex prevention device.

Background Art

[0002] When rainfall exceeding the drainage capacity of a drainage station occurs, there is a risk of river flooding and inundation damage to houses. In recent years, due to the tendency of increasing rainfall accompanying climate change, the risk of flooding and the like has been increasing. For this reason, the necessity of enhancing the drainage capacity in existing drainage stations is increasing.

[0003] In enhancing the drainage capacity, it is conceivable to install a large drainage pump. However, since it is necessary to increase the size of the drainage pump while considering the usage conditions and installation location constraints, a great deal of manufacturing cost and a long manufacturing period are required. Further, simply increasing the size of the drainage pump has a problem from the viewpoint of risk dispersion such as flooding because the drainage capacity significantly decreases during maintenance or failure of the pump.

[0004] On the other hand, it is conceivable to install a large number of drainage pumps in an existing drainage station to enhance the drainage capacity while dispersing the risk (see, for example, Patent Document 1). When installing a large number of drainage pumps, it is conceivable to suck water from an outdoor suction inflow part or from a suction water tank arranged directly below the existing pump room. In the latter case, it is necessary to form an opening in the existing suction water tank (civil engineering structure), which causes a decrease in the strength of the structure. In the former case, when installing a large number of drainage pumps in an existing drainage station, water is sucked from the outdoor suction inflow part, but at present, the installation space in the existing drainage station is limited.

[0005] In addition, when installing a large number of drainage pumps and thus a large number of suction pipes, it is often impossible to ensure a sufficient distance between adjacent suction pipes. As a result, the Karman vortices generated from other suction pipes may develop, leading to the generation of air suction vortices. Moreover, due to differences in the water inflow conditions between the existing drainage pump station and the new installation, the water flow at the suction inlet may become uneven, or the approaching flow velocity of water in the suction pipe may increase, which may also cause the generation of underwater vortices or air suction vortices. Therefore, when installing multiple suction pipes, it is necessary to take vortex countermeasures within the limited space.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide a vortex prevention device and a pump device capable of achieving space saving of equipment while taking vortex prevention measures for suction pipes.

Means for Solving the Problems

[0008] In view of the above, one aspect of the present invention is a pump device including a plurality of pump units for transferring water from a suction inlet portion to a discharge water tank, and a vortex prevention device attached to the pump units. The pump unit includes a suction pipe partially disposed in the suction inlet portion, a pump portion connected to the suction pipe, and a drive source for driving the pump portion. Two adjacent pump units are arranged such that the corresponding two suction pipes form a predetermined angle. The vortex prevention device is disposed radially outside the diameter of the suction port of the suction pipe, and includes an air vortex prevention plate extending substantially horizontally from the suction ports of the plurality of pump units. The vortex prevention device also includes an underwater vortex prevention plate extending substantially vertically from the suction port. This prevents the formation of air suction vortices and underwater vortices in the suction inlet portion.

[0009] One aspect of the present invention is a vortex prevention device attached to a plurality of pump units including a suction pipe partially disposed within a suction inflow section, a pump section connected to the suction pipe, and a drive source for driving the pump section. The vortex prevention device is disposed radially outside the diameter of the suction port of the suction pipe and includes an air vortex prevention plate that extends substantially horizontally from the suction ports of the plurality of pump units. Further, the vortex prevention device includes a water vortex prevention plate that extends substantially vertically from the suction port. Thereby, formation of an air suction vortex and a water vortex in the suction inflow section is prevented.

Effects of the Invention

[0010] According to the present invention, it is possible to save space in the pump facility while taking measures to prevent vortices in the suction piping.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Best Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of the pump device 10 in the present embodiment, and FIG. 2 is a side view of the pump device 10. The pump device 10 in the present embodiment is installed, for example, at a drainage station and constitutes a drainage system for draining rainwater flowing into the suction inflow section from a river or the like into the discharge water tank.

[0013] The pump device 10 includes three pump units 10A to 10C and a vacuum pump 12 commonly connected to these pump units 10A to 10C. Each of the pump units 10A to 10C has a suction pipe that penetrates an opening (not shown) formed in the building wall 14 and is disposed on the civil engineering structure floor 16 integrally formed with the building wall 14. The inside of the civil engineering structure floor 16 is an existing suction water tank or the ground 18.

[0014] In this specification, since the configurations of the pump units 10A to 10C are common, unless otherwise specified, the pump unit 10A will be described below. Note that the configurations with the endings of the reference numerals being a to c respectively mean the configurations of the pump units 10A to 10C.

[0015] In FIG. 3, the pump unit 10A is a horizontal axis pump and has a suction pipe 20a, a pump section 22a, a discharge pipe 24a, and a discharge valve 26a. One end side (the side of the suction inflow section) of the suction pipe 20a has a bellmouth opening, and the other end side (the discharge side) opening is connected to the pump section 22a. One end side (the suction side) opening of the pump section 22a is connected to the suction pipe 20a, and the other end side (the discharge side) opening is connected to the discharge pipe 24a. One end side (the suction side) opening of the discharge pipe 24a is connected to the pump section 22a, and the other end side (the discharge side) opening is directed toward a discharge water tank (not shown). The discharge valve 26a is provided in the discharge pipe 24a.

[0016] The pump unit 10A has a prime mover 30a and a speed reducer 32a having an input shaft and an output shaft. The prime mover 30a is connected to the input shaft of the speed reducer 32a, and the output shaft of the speed reducer 32a is connected to a main shaft (not shown) in the pump section 22a. The speed reducer 32 has a predetermined reduction ratio such that the ratio of the rotational speed of the input shaft to the rotational speed of the output shaft is a predetermined value. When the prime mover 30a rotates, the rotational force is transmitted to the main shaft in the pump section 22a via the speed reducer 32a, and an impeller (not shown) connected to the main shaft rotates. As a result, water is guided from the suction pipe 20a through the pump section 22a to the discharge pipe 24a.

[0017] The pump unit 10A further has an intake valve 36a, a vacuum breaker valve 38a, and a full water detector 40a (in FIG. 3, these members are shown collectively for simplification). The pump section 22a is connected to the vacuum pump 12 via the intake valve 36a. When the vacuum pump 12 is driven with the intake valve 36a open, the inside of the pump section 22a is evacuated. The vacuum breaker valve 38a is provided in the suction pipe 20a, the pump section 22a, or the discharge pipe 24a. When the vacuum breaker valve 38a opens, the vacuum state of the internal space from the suction pipe 20a to the discharge pipe 24a is broken, and the atmospheric pressure is restored.

[0018] The full water detector 40a detects that the space from the suction pipe 20a to the discharge valve 26a (the internal space of the pump unit 10A) is full of water. When the full water detector 40a detects full water, the impeller in the pump section 22a rotates by the prime mover 30a, and further the discharge valve 26a opens. As a result, water is pumped up from the suction inflow section and transferred to the discharge water tank.

[0019] The angle θ (see FIG. 1) formed between the direction in which the suction pipe 20a of the central pump unit 10A extends and the directions in which the suction pipes 20b and 20c of the adjacent pump units 10B and 10C extend is preferably less than 90 degrees, more preferably 45 degrees or less. By arranging the adjacent suction pipes obliquely, the required installation width (the width required in the direction perpendicular to the discharge pipe) can be reduced, and space can be saved while improving the processing capacity of the pump device.

[0020] At the lower end (suction port 42a) of the suction pipe 20a, a vortex prevention device 50 according to this embodiment is attached. As shown in FIGS. 4 and 5, the vortex prevention device 50 has an air vortex prevention plate 52 that extends in a substantially horizontal direction from the suction port 42a. The air vortex prevention plate 52 has a sector shape as a whole and has an arcuate outer edge portion, and is attached so as to straddle not only the suction pipe 20a but also the suction ports 42b and 42c of the other two adjacent suction pipes 20b and 20c. The air vortex prevention plate 52 is fixed to the suction pipes 20a to 20c by a fastening tool such as a bolt (not shown) or welding.

[0021] An air suction vortex is generated when the Karman vortex generated when the flow of water forming the free surface is diverted by the suction pipe 20a develops. The Karman vortex is generated on the downstream side of the suction pipe 20a and is flowed downstream by the flow of water (see the arrow in FIG. 1). As shown in FIGS. 1 and 2, there is only the building wall 14 in the suction inflow portion, and the flow direction of the suction inflow portion flowing into the suction pipe is unspecified except for the direction from the building wall 14, and it will flow toward the suction pipe except for the direction from the building wall 14. For this reason, the air vortex prevention plate 52 is attached to the downstream side of the suction pipes 20a to 20c with respect to the flow of water. As long as it is the downstream side, the joining portion of the air vortex prevention plate 52 to the suction pipes 20a to 20c is not particularly limited, and it may be fixed to the outer peripheral surface on the lower end side of the suction pipe 20a as shown in FIG. 4, or may be fixed below the suction ports 42a to 42c.

[0022] In FIG. 4, the air vortex prevention plate 52 has a shape that surrounds at least a part of the suction ports 42a to 42c, but the air vortex prevention plate 52 may be arranged so as to surround the entire circumference of the suction ports 42a to 42c, but preferably it is less than half the circumference of the suction ports 42a to 42c.

[0023] Generally, the gentler the free surface of the water flowing through the suction inflow portion, the easier it is for vortices to occur. The state of the free surface of the water can be evaluated by the Froude number defined by the following formula. Froude number (Fr) = v / (gh) 1 / 2 ···(1) Here, v represents the flow velocity of water, g represents the acceleration due to gravity, and h represents the water depth. As the Froude number approaches 1, the water surface becomes wavy, and as the Froude number approaches 0, the water surface becomes calm. Also, as can be seen from Equation (1), the higher the water level, the closer the Froude number approaches 0 (vortices are more likely to occur).

[0024] As shown in FIG. 2, since the air vortex prevention plate 52 protrudes horizontally, the apparent water depth h’ at low water levels becomes shallower than the actual water depth h (h’ < h). For this reason, the free surface of the water flowing through the suction inflow portion is disturbed, and the Froude number increases. Also, even when a Karman vortex occurs, it is blocked by the horizontally protruding vortex prevention plate, so the growth from the Karman vortex to the air suction vortex can be prevented.

[0025] In this way, by providing the air vortex prevention plate 52, the air suction vortex that may occur when the suction inflow portion is at a low water level can be effectively prevented. Also, since the air vortex prevention plate 52 does not obstruct the flow of water flowing into the suction port 42a, the performance of the pump device is not impaired.

[0026] Also, as shown in FIG. 5, the vortex prevention device 50 according to the present embodiment further includes a wing portion 54 protruding vertically from the outer edge of the air vortex prevention plate 52. The air vortex prevention plate 52 and the wing portion 54 of the vortex prevention device 50 are integrally formed.

[0027] When the water level of the suction inflow portion is high, the free surface of the water is relatively calm and the actual lift is low, so the flow rate of the water transferred by the pump increases. Therefore, when the water level becomes high to a certain extent, vortices may be likely to occur. In the present embodiment, a stagnant portion is generated near the vertically protruding wing portion 54, and this disturbs the flow of the water in the path of the vortex, thus preventing the vortex from reaching the suction port 42a. Therefore, by providing the wing portion 54, the formation of the air suction vortex at high water levels can be effectively prevented.

[0028] In addition, the vortex prevention device according to the present embodiment includes bell splitters (submerged vortex prevention plates) 56a to 56c attached to the lower ends of the suction ports 42a to 42c of the respective suction pipes 20a to 20c. As shown in FIG. 6, the bell splitter 56a has a structure in which three plate portions symmetrically arranged at an angle of approximately 120 degrees to each other are integrated, and prevents the generation of vortices by preventing the swirling flow that may occur near the pump. Although not shown, the other bell splitters 56b and 56c also have the same shape as the bell splitter 56a in FIG. 6.

[0029] By providing the vortex prevention device including these air vortex prevention plates and bell splitters, it is possible to effectively prevent the formation of vortices (air suction vortices and submerged vortices) that may occur near the suction ports 42a to 42c of the pump device 10. Note that a vortex prevention device omitting the bell splitter may be used, and even in this case, the formation of air suction vortices can be effectively prevented.

[0030] FIG. 7 is a flowchart showing an example of the start-up procedure of the pump unit in the pump device according to the above configuration. The order in which the plurality of pump units 10A to 10C are started may be fixed or may be changed sequentially. Hereinafter, the pump unit 10A will be described as the first operating unit. In the following description, the start-up and stop control of the pump units 10A to 10C may be configured to be automatically performed by a control device (not shown) connected to the pump device, or the operator may manually operate a control panel (not shown) to start and stop the pump units 10A to 10C.

[0031] First, as an initial condition, the discharge valve 26a of the pump unit 10A, which is the first operating unit, is in a closed state. Also, the intake valve 36a is in a closed state, and the vacuum breaker valve 38a is in an open state (step S10). As a result, the space from the suction pipe 20a to the discharge valve 26a is in an open state to the atmosphere.

[0032] Also, as initial conditions, the discharge valves 26b and 26c of the other pump units 10B and 10C are both in the closed state. Also, similar to the first pump unit 10A, the intake valves 36b and 36c of the other pump units 10B and 10C are in the closed state, and the vacuum break valves 38b and 38c are in the open state.

[0033] When it is detected by a water level gauge (not shown) provided in the suction inflow section that the water level in the suction inflow section is equal to or higher than the height of the suction port 42a of the suction pipe 20a and is also equal to or higher than the first operating water level (''Y'' in step S11), the intake valve 36a is opened and the vacuum break valve 38a is closed, and the vacuum pump 12 is operated (step S12). As a result, the space from the suction pipe 20a to the discharge valve 26a is evacuated.

[0034] When it is detected by the full water detector 40a that the space from the suction pipe 20a to the discharge valve 26a is full of water (''Y'' in step S13), the intake valve 36a is closed and the vacuum pump 12 is stopped (step S14).

[0035] Then, the prime mover 30a is operated to rotate the impeller of the pump section 22a (step S15), and the discharge valve 26a of the pump unit 10A is opened (step S16). By the above operations, the water in the suction inflow section is pumped up by the first pump unit 10A and drained toward the discharge water tank.

[0036] FIG. 8 is a flowchart showing an example of the start-up procedure of the pump unit related to the second operating unit of the pump device. Hereinafter, the description will be made assuming that the pump unit 10B is the second operating unit.

[0037] In the initial state, the discharge valve 26b of the pump unit 10B that becomes the second operating unit is in the closed state. Also, the intake valve 36b is in the closed state, and the vacuum breaker valve 38b is in the open state (step S20). As a result, the space from the suction pipe 20b to the discharge valve 26b is in the state of being open to the atmosphere. Note that the discharge valve 26a of the pump unit 10A related to the first operating unit is in the open state. Also, for the third pump unit 10C, the discharge valve 26c is in the closed state.

[0038] After that, when it is detected that the water level in the suction inflow section is equal to or higher than the height of the suction port 42b of the suction pipe 20b and reaches the second operating water level ( "Y" in step S21), the intake valve 36b is opened, the vacuum breaker valve 38a is closed, and the vacuum pump 12 is operated (step S22). As a result, the space from the suction pipe 20b to the discharge valve 26b is evacuated. When it is detected by the full - water detector 40b that the space from the suction pipe 20b to the discharge valve 26b is full of water ( "Y" in step S23), the intake valve 26b is closed and the vacuum pump 12 is stopped (step S24). Then, the prime mover 30b is operated to rotate the impeller of the pump section 22b (step S25), and the discharge valve 26b of the pump unit 10B is opened (step S26). By the above operations, the water in the suction inflow section is pumped up by the second pump unit 10B and drained toward the discharge water tank.

[0039] Since the start - up procedure of the pump unit related to the third operating unit is the same as that in FIG. 8, the description is omitted.

[0040] FIG. 9 is a flowchart showing an example of the stop procedure of the pump unit related to the first operating unit. When a plurality of pump units 10A to 10C are driving, the order in which they are stopped may be fixed or may be changed sequentially. Hereinafter, the description will be made assuming that the pump unit 10A is stopped first.

[0041] When it is detected that the water level at the suction inlet has dropped below a predetermined value while the pump unit is in operation (i.e., "Y" in step S30), the discharge valve 26a of the pump unit 10A that is in the open state is closed (step S31). Then, the prime mover 30a is stopped according to the water level in the suction water tank (step S32). As a result, the pump unit 10A stops draining water from the suction inlet to the discharge water tank. Since the stop procedures for the second and subsequent pump units are the same, the description thereof is omitted.

[0042] In the above-described embodiment, a pump device composed of three pump units has been described as an example. However, the present invention is not limited thereto, and can be equally applied to cases where two or four or more pump units are provided. When using four or more pump units, a single guard house may be used, or a vortex prevention device may be configured from a plurality of guard houses. Alternatively, a plurality of the above-described pump devices composed of three pump units may be installed. For example, when nine pump units are provided, three pump devices may be arranged side by side at the drainage site.

[0043] In the above-described embodiment, the outer edge shape of the air vortex prevention plate 52 is an arc shape. However, the present invention is not limited thereto, and the outer peripheral edge may be composed of a plurality of straight lines such that the air vortex prevention plate 52 is a polygon such as a rectangle or a pentagon.

[0044] In the above-described embodiment, the case of using an integrated air vortex prevention plate 52 coupled to a plurality of suction pipes 20a to 20c has been described as an example. However, the present invention is not limited thereto. As shown in FIG. 10, vortex prevention plate units 58a to 58c corresponding to each of the suction pipes 20a to 20c may be provided, and these vortex prevention plate units 58a to 58c may be configured to be coupled by a fastener 60 using bolts and nuts. Thereby, the size of the vortex prevention plate becomes smaller compared to the case of integration, and the work of transporting it to the drainage site can be made more efficient.

[0045] In the above-described embodiment, the suction pipe and the discharge pipe of the pump unit are configured to be parallel. However, the present invention is not limited to this. For example, as shown in FIG. 11, while maintaining the angle θ formed by the suction pipes of adjacent pump units, the discharge pipes may be arranged so as to be substantially parallel. Thereby, the space saving of the entire pump device can be achieved.

[0046] The above-described embodiments are described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention pertains to practice the present invention. Various modifications of the above embodiments can be naturally made by those skilled in the art, and the technical idea of the present invention can also be applied to other embodiments. The present invention is not limited to the described embodiments, but is construed in the broadest scope in accordance with the technical idea defined by the claims.

Explanation of Reference Numerals

[0047] 10 Pump device 10A to 10C Pump units 20a to 20c Suction pipes 22a to 22c Pump sections 26a to 26c Discharge valves 30a to 30c Prime movers 50 Vortex prevention device 52 Submerged vortex prevention plate 54 Wing section 56a to 56c Belt splitters 58a to 58c Vortex prevention plate units

Claims

1. A pump device comprising a plurality of horizontal axis pump units for transferring water from a suction inflow section to a discharge water tank, and a vortex prevention device attached to the horizontal axis pump units, The horizontal axis pump unit includes a suction pipe partially disposed in the suction inflow section, a pump section connected to the suction pipe, and a drive source for driving the pump section, Two adjacent horizontal axis pump units are arranged such that the angle formed by the corresponding two suction pipes in a plan view is a predetermined angle greater than 0 degrees and less than 90 degrees, The vortex prevention device is disposed radially outside the diameter of the suction port of the suction pipe, and includes an air vortex prevention plate extending substantially horizontally from the suction ports of the plurality of horizontal axis pump units, and is characterized by preventing the formation of an air suction vortex in the suction inflow section. Pump device.

2. The pump device according to claim 1, wherein the vortex prevention device includes a wing portion extending upward from an outer edge portion of the air vortex prevention plate.

3. The pump device according to claim 1 or 2, wherein the vortex prevention device further includes a subaqueous vortex prevention plate provided below the suction port of the suction pipe.

4. The air vortex prevention plate includes a plurality of vortex prevention plate units provided corresponding to each of the suction pipes, and a fastener for fastening the plurality of vortex prevention plate units. The pump device according to any one of claims 1 to 3.

5. The pump device according to any one of claims 1 to 4, wherein the air vortex prevention plate is disposed on the downstream side of the suction pipe with respect to the flow direction of water in the suction inflow section.

6. A vortex prevention device attached to a plurality of horizontal axis pump units including a suction pipe partially disposed in a suction inflow section, a pump section connected to the suction pipe, and a drive source for driving the pump section, A fan-shaped air vortex prevention plate having an outer edge portion on an arc and a mounting portion formed on the opposite side of the outer edge portion, wherein the mounting portion has a shape straddling a plurality of the suction pipes constituting the plurality of horizontal axis pump units. The air vortex prevention plate is attached to the plurality of horizontal axis pump units so as to extend substantially horizontally from the plurality of suction pipes, thereby preventing the formation of air suction vortices in the suction inflow portion.

7. The air vortex prevention plate according to claim 6, wherein the air vortex prevention plate is attached to the plurality of horizontal axis pump units such that the outer edge portion is disposed on the downstream side of the suction pipe with respect to the flow direction of water in the suction inflow portion.

Images