JP2002155898A - Pump vortex breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of an air suction vortex with simple structure, without carrying out civil engineering works for vortex prevention. SOLUTION: A subpassage forming member 28 for forming a subpassage 30 between the subpassage forming member 28 and an outer peripheral surface of the suction part 14 is approximately concentrically arranged on an outer periphery of the suction part 14 having a suction opening 14a arranged to an open channel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump device such as a circulating water pump used for a pump water supply / drainage facility or a power plant, and more particularly to a pump device installed in a pump pit for pumping water in the pump pit. In particular, the present invention relates to a pump vortex prevention device that prevents generation of an air suction vortex and a water vortex.

[0002]

2. Description of the Related Art For example, in a generally used open water channel (open water channel), as shown in FIG. A suction port 14 at the lower end of the suction bell mouth 14 is connected to a pump to which the suction section 14 is connected.
a is installed so as to be submerged in water, and by driving this pump, water in the pump pit 10 is sucked up. In this case, since the water around the suction port 14a has a free surface, when the immersion depth S is small or when the flow velocity V is large, the air suction vortex A connected from the water surface to the suction port 14a by the vortex L is formed. Occurs, or the suction port 1
Underwater vortex B leading to 4a may be generated, and vibration or noise may be generated which hinders pump operation.

For this reason, as shown in FIG. 25, a vortex preventing horizontal plate 16 having a semicircular notch 16a surrounding the suction casing 12 is provided inside the pump pit 10 on the peripheral wall 10a of the pump pit 10. Mounting and installation,
A vortex preventing vertical plate (splitter) 18 extending in an L-shape along the flow direction from the side of the suction casing 12 to below the suction bell mouth 14 is attached to the peripheral wall 10 of the pump pit 10.
a and the bottom wall 10b.

As shown in FIGS. 26 and 27, an annular frame 152 having a diameter larger than the diameter of the suction pipe 150 is concentrically attached to a lower end of the suction pipe 150 via a support rod 154. The frame 152 is connected to the suction port 1 of the suction pipe 150.
A turbulent layer 158 reaching the suction port 150a of the suction pipe 150 from the frame 152 is formed so as to cross the flow 156 in the water channel toward the flow path 50a, thereby preventing the generation of the air suction vortex. Is being developed.

[0005]

However, in the conventional example shown in FIG. 25, it is necessary to mount a horizontal plate or splitter for preventing vortices on the peripheral wall or bottom wall of the pump pit and to install it in the pump pit. There is a need for a separate civil engineering work, which not only increases construction costs, but also adds a horizontal plate or splitter for preventing vortices to the surrounding wall or bottom wall of the existing pump pit. There is a problem that it is often very difficult to install.

Further, in the conventional example shown in FIGS. 26 and 27, the flow vortex 2A passing just inside the frame 152 is sucked from the vicinity of the water surface causing the air suction vortex. Although the midway of the flow vortex 2A toward 150a is disturbed by the turbulent layer 158, the air suction vortex can be eliminated, but the flow vortex 1A from the vicinity of the suction pipe 150 to the suction port 150a and the frame 152 Suction port 150 from outside
With respect to the flow vortex 3A heading toward a, the flow vortex 1A, 3A cannot be disturbed in the turbulent layer 158, and the air suction vortex may be generated at a position avoiding the obstacle. Because of the large number, the vortex prevention effect is considered to be small.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a relatively simple structure and can prevent the occurrence of an air suction vortex without performing civil engineering work for vortex countermeasures. It is an object to provide a vortex prevention device.

[0008]

According to a first aspect of the present invention, there is provided a suction device having a suction port provided in an open channel and having a gap between the suction portion and an outer peripheral surface thereof. A pump vortex prevention apparatus, wherein a sub-flow path forming body that forms a passage is disposed substantially concentrically.

As a result, the flow from the water surface side to the suction port of the suction portion is divided into a main flow and a sub-flow flowing along the sub-flow passage, and a strong local downward flow causing air suction vortices is generated. The occurrence of the air suction vortex can be prevented. In addition, vortex countermeasures can be taken by arranging the sub-flow path forming member on the outer periphery of the suction portion, so that there is no need to install a vortex prevention structure in the pump pit. In other words, the civil structure of the pump pit requires only a simple square tank, and the construction cost is very low.

[0010] The invention according to claim 2 is characterized in that the sub-flow path forming body is disposed substantially horizontally at a position separated from the suction port of the suction section by a predetermined distance. Item 4. A pump vortex prevention device according to Item 1.

The invention according to claim 3 is characterized in that the sub-flow path forming body is formed in a substantially cylindrical shape and is arranged so as to surround the suction portion with a predetermined space therebetween. The pump vortex prevention device according to claim 1.

According to a fourth aspect of the present invention, there is provided any one of the first to third aspects, wherein a flat object for preventing the formation of a surface vortex is provided above the suction port of the sub-flow path forming body. It is a pump vortex prevention device as described. Thus, it is possible to prevent the surface vortex from being generated just above the sub-flow path inlet, and to collapse the vortex passing through the sub-flow path.

[0013] The auxiliary flow path forming body may be supported by the suction portion so as to be able to expand in diameter. By this, for example, when applying eddy countermeasures by retrofitting, by folding the sub-flow path forming body, inserting the opening for pump installation, and then expanding the sub-flow path forming body, the diameter of the larger diameter than the opening size The sub flow path forming body can be arranged on the outer periphery of the suction section.

According to a fifth aspect of the present invention, there is provided the pump vortex prevention apparatus according to any one of the first to fourth aspects, wherein a swirl flow prevention plate is attached to the auxiliary flow path forming body.
Accordingly, even if a swirl flow that causes a vortex is generated around the pump, the swirl flow around the pump is suppressed by the ribs, so that the generation of the air suction vortex and the underwater vortex can be prevented.

[0015]

FIG. 1 is a block diagram showing an embodiment of the present invention.
23 will be described with reference to FIG. FIGS. 1 and 2 show a pump vortex prevention device according to a first embodiment of the present invention. The pump device includes a discharge bowl (pump casing) 22 containing an impeller 20 and the like therein. A suction bell mouth structure 24 is connected to the lower end of the discharge bowl 22.

The suction bell mouth structure 24 includes a suction bell mouth (suction portion) 14 and ribs 2 arranged on the outer peripheral surface of the suction bell mouth 14 at a predetermined pitch along a circumferential direction.
And a sub-flow path forming plate (sub-flow path forming body) 28 in the form of a hollow disk attached through the intermediary 6. The sub-flow path forming plate 28 is disposed substantially horizontally.

The sub-flow path forming plate 28 is located at a position covering the suction port 14a of the suction bell mouth 14, that is, in the hollow portion 28a of the sub-flow path forming plate 28.
4 is located at a position where a gap is formed between the plane formed by the suction port 14a and the lower surface of the sub-flow path forming plate 28, and is positioned below the lowest water level LWL of the flow path. . As a result, a sub flow path 30 is formed between the suction bell mouth 14 and the sub flow path forming plate 28. Dimension C ₁ at the position of the suction bell mouth diameter D of the gap is, the opening area [pi] D · C formed by the dimensions
_1, with respect to the area [pi] D ^2/4 of the pump suction port AD at the suction bell mouth diameter D, it is appropriate to determine the order of 20% to 70%.

The larger the width K of the sub-flow path forming plate 28 is, the larger the vortex prevention effect is. However, if the width K is about 0.2 to 0.3 D or more with respect to the suction bell mouth diameter D, the vortex prevention effect becomes remarkable. Become. Further, as shown in FIG. 2, the size of the auxiliary flow channel formation plate 28 is set from the outer peripheral edge of the suction bell mouth 14 so as to have an overhang K _1. Portions K ₂ excluding the overhanging portion K ₁ from the width K of the auxiliary flow path forming plate 28 is not necessarily required.

The ribs 26 have an effect of circumferentially dispersing the flow from the vicinity of the water surface, which causes air suction vortices, to the suction port 14a. And the eddy prevention effect is large.
Therefore, for example, as shown in the figure, it is better to have about eight sheets.

According to this embodiment, when the pump vortex prevention device is installed in the pump pit 10 and the pump is driven to pump water in the pump pit 10, the flow from the water surface side to the suction port 14a is The main flow F is diverted into the sub flow G along the sub flow passage 30 formed between the suction bell mouth 14 and the sub flow passage forming plate 28, so that a strong local downward flow does not occur. In addition, the generation of the air suction vortex is prevented. In addition, the rib 26 for attaching the sub-channel forming plate 28
The suction port 14a is located near the water surface, which causes the air suction vortex.
Has the effect of circumferentially dispersing the flow heading toward it, which also makes it difficult for locally strong downward flows to occur,
A vortex prevention effect can be promoted.

Furthermore, since the suction bell mouth structure 24 is connected to the lower end of the discharge bowl 22 to take measures against vortices, it is not necessary to install a structure for preventing vortices in the pump pit 10. For the civil structure of the pump pit 10, only a simple square tank needs to be prepared, and the construction cost is very low.

In this example, as the sub-flow path forming body,
Although an example in which a hollow disk-shaped sub-flow path forming plate 28 is used is shown, a rectangular sub-flow path having a hollow portion as shown by a solid line in FIG. Road forming plate 3
2 or a polygonal shape, or as shown by a broken line in FIG.
Alternatively, as shown by a two-dot chain line in FIG. 3, a sub-flow path forming plate 36 having a hollow portion and having an arbitrary shape such as a circular shape on the upstream side and a rectangular shape on the downstream side may be used.

As shown in FIG. 4A, a hollow slit is formed in a hollow disk-shaped sub-channel forming plate 28 to divide it into a plurality of (four in the figure) divided pieces 28b. FIG.
As shown in (b), the split piece 28b may be provided only at an arbitrary position such as on the downstream side of the pump where air suction vortices easily occur.

Further, as shown in FIG. 5, a ring-shaped pipe 38 is used as the sub-flow path forming body.
The sub flow path 30 may be formed between the suction bell mouth 14 and the outer peripheral surface thereof. In this example, four ring-shaped pipes 38 are used, and the pipes 38 are arranged in parallel and slightly along the outer peripheral surface of the suction bell mouth 14. However, even one pipe is used. Of course, it may be wound spirally.

FIGS. 6 and 7 show a pump vortex prevention apparatus according to a second embodiment of the present invention. This apparatus is a substantially cylindrical auxiliary in which the outer periphery of a suction bell mouth 14 is similarly enlarged. A suction bellmouth structure 44 is constituted by surrounding the flow passage forming plate (sub-flow passage forming member) 40 with a predetermined interval via a rib 42, and the outer peripheral surface of the suction bell mouth 14 and the sub-flow passage forming plate 40 are formed. A substantially constant dimension C ₂ over almost the entire surface
A sub-flow passage 46 having a gap having the above-mentioned shape is formed.

The dimension C ₂ of the gap of the auxiliary flow channel 46 is substantially may be constant from the inlet of the auxiliary flow channel 46 to the outlet, the structure of the pump, it is better to change the flow area of the inlet and outlet. That is, the area of [pi] D ^2/4 of the pump suction port AD, the area 30 to 100% of the sub-passage inlet A1, the area of the auxiliary flow channel outlet A2 is dimensioned such that approximately 50% to 150% Is appropriate. Height _{L 1} of the sub-channel 46, 0.
If it is 15D or less, the vortex prevention effect is small, and therefore it is preferable to be more than 15D. The sub flow path forming plate 40 may be replaced with a commercially available straight pipe.

Even in this embodiment, when pumping water,
The flow from the water surface side to the suction port 14a is divided into a main flow F and a sub flow G along a sub flow path 46 formed between the suction bell mouth 14 and the sub flow path forming plate 40, and the air suction vortex is formed. A
The strong downward flow is suppressed in the process of developing the airflow, and the downward flow is divided into the main flow F and the subflow G, so that the vortex becomes unstable and the generation of the air suction vortex is prevented. The flow dividing effect is also promoted by the ribs 42 on which the sub flow path forming plate 40 is mounted.

According to this embodiment, by using a cylindrical auxiliary flow-path forming plate 40 may be as shown in FIG. 7, to reduce the maximum diameter d ₄ of the outlet side. Also,
The inlet diameter d ₃ of the auxiliary flow channel formation plate 40 is made smaller than the maximum diameter d ₂ of the discharge bowl 22, it was difficult to immediately vortex on the formation of the auxiliary flow channel inlet, further increase the vortex prevention effect Can be. As shown in FIG. 8, if the pump maximum diameter d ₂ is smaller in the discharge bowl 22, suction bell mouth 1
The fourth flange 14b is set to be larger than the inlet diameter d ₃ of the auxiliary flow channel formation plate 40, it is possible to increase the vortex prevention effect for the same reason as described above. In this case, the flange 14b of the suction bell mouth 14 is installed so as to be located below the minimum water level LWL.

[0029] Figure 9 is installed a hollow disk-shaped auxiliary top plate 136 at a gap of predetermined dimension C ₃ above the auxiliary flow channel formation plate 40, whereby the flange 1 of the intake bellmouth 14
The same effect as described above can be obtained without increasing 4b. The auxiliary top plate 136 is set to a size which protrudes outside and inside around the inlet diameter d ₃ of the auxiliary flow channel formation plate 40 is installed so as to be positioned below the lowest water level LWL. Sub flow path forming plate 40 and sub top plate 13
Dimensions C ₃ with 6, for example, the area formed by the dimension C _3, is set to be 0.3 to 0.8 times the area of the auxiliary flow channel inlet A1. In addition, suction bell mouth 1
4 horizontal gap dimension C between the outer wall and the auxiliary top plate 136
_In No. ₄ , for example, the area formed by the dimension C ₄ is set to about の of the area of the sub-channel inlet A1.
With such a structure, the flange 1 shown in FIG.
In addition to the vortex prevention effect corresponding to 4b, the sub-flow G can be further divided into _two branch flows G ₁ and G ₂ to increase the vortex prevention effect.

Here, as shown in FIG. 10, a second sub-flow path forming plate 40a is disposed outside the sub-flow path forming plate 40 via a second rib 42a at a predetermined interval. A second sub-channel 46a may be formed between the two sub-channel forming plates 40, 40a.

As shown in FIG. 11, the sub-flow path forming plate 40 has, for example, a wing shape in which the upper end is thick and has a large radius and gradually becomes thinner toward the lower end. The rib 42 has an upper edge extending upward from the upper end of the sub-flow path forming plate 40 in an arc shape, using a rib having a velocity difference in the flow along the front and back surfaces of the path forming plate 40. and lower edge may be the length L ₂ along the auxiliary flow channel 46 of the auxiliary flow channel formation plate 40 reaching the lower end of the auxiliary flow channel formation plate 40 using a sufficiently long.

As described above, by providing a velocity difference in the flow along the front and back surfaces of the sub-flow path forming plate 40, it is possible to prevent dust from being wound around the upper edge portion, the length L ₂ along the 46 by sufficiently long, the ribs 42
It is possible to prevent dust from winding around the upper edge.
The length _{L 2} is, for example, about 250 mm. In addition,
The rib 42 has a sectional shape similar to that of the sub-flow path forming plate 40, for example, has a wing shape, and a velocity difference is generated in the flow along each of the left and right surfaces thereof. The effect of preventing dust from being wound around the upper edge can be promoted.

Further, as shown in FIG. 12, as the rib 42, an arc-shaped rib having a transverse cross section along one direction is used, and a rib 42 between the sub-flow path forming plate 40 and the suction bell mouth 14 is used. A circumferential pre-swirling flow Q may be given to the flow along the flow path 46. Accordingly, for example, as shown in FIG. 12, when the turning direction of the submersible vortex B is always constant, the sub-flow passage 46 is directed along the direction in which the submersible vortex B collides with (turns off) the turning direction of the submersible vortex B. By giving the pre-swirling flow Q to the sub flow, the generation of the underwater vortex B can be prevented.

FIG. 13 shows a pump swirl prevention device according to a third embodiment of the present invention. This device has a flange 12a at the lower end of the suction casing 12, and a flange 14b at the upper end of the suction bell mouth 14. The suction bell mouth 14 was connected to the lower end of the suction casing 12 via the flanges 12a and 14b, and was further bent toward the suction port 14a at the lower end of the sub-passage forming plate 40 in the second embodiment. The suction bell mouth structure 44a is constituted by connecting the guide portions 48 integrally. Other configurations are the same as those of the second embodiment.

According to this embodiment, the sub flow passage 46 formed between the suction bell mouth 14 and the sub flow passage forming plate 40 is formed.
Of the air suction vortex drawn from the water surface by the sub flow G along the
a, 14b to promote the vortex prevention effect,
Further, by smoothly flowing the auxiliary flow G into the suction port 14a via the guide portion 48, the inlet loss at the suction port can be reduced.

FIG. 14 shows that the pump vortex prevention apparatus of this embodiment can be operated even when the water level is very low. When the water level is equal to or higher than the minimum water level LWL, generally no vortex is generated. However, as shown in the figure, when the water level falls below the flange 14b of the suction bell mouth 14, the vortex prevention effect is reduced, and the air suction vortex A as shown in the figure is reduced. Is more likely to occur. However, even in such a situation, the sub flow path 46
May be reduced and the number of ribs 42 arranged at a predetermined pitch in the circumferential direction may be increased to subdivide the passage of the sub flow passage 46. In this way, even if the air suction vortex A passing through the sub flow path 46 is generated, it becomes weak and small, and the impact when the vortex passes through the impeller becomes small. It is possible to avoid trouble. That is, the air suction vortex is transferred to the sub-flow path forming plate 40 and the rib 42.
Suction mouth 14a of suction bell mouth 14
By introducing air into the pump, it becomes possible to inject air into the pump, and a preliminary standby operation at all water levels becomes possible without using a conventionally used air pipe.

FIG. 15 shows a pump vortex prevention device according to a fourth embodiment of the present invention. This device is provided at a lower end of a suction casing 12 with a sub-flow passage having the same structure as that of the first embodiment. The upper swirl flow prevention plate 52 and the lower swirl flow prevention plate 54, which extend linearly along the flow direction and extend vertically, are attached to the upper and lower surfaces of the sub-flow path formation plate 28, respectively. This constitutes a bellmouth structure 24a. Other configurations are the same as in the first embodiment.

According to this embodiment, even if the swirl flow R is generated around the pump by the upper swirl flow prevention plate 52 and the lower swirl flow prevention plate 54, the swirl flow R causes the air suction vortex and the underwater vortex. Generation can be prevented. The second
The same effect can be obtained by attaching the swirling flow prevention plate having such a configuration to the outer peripheral surface of the cylindrical sub-flow path forming plate in the embodiment.

FIG. 16 shows a pump vortex prevention apparatus according to a fifth embodiment of the present invention.
The suction bell mouth structure 24 having the same structure as that of the first embodiment is attached to the suction bell mouth 14 in which a bottom plate 62 having
b. Other configurations are the same as in the first embodiment.

FIG. 17 shows a pump vortex prevention apparatus according to a sixth embodiment of the present invention in which a pump is installed on the bottom of a water tank. This is achieved by attaching a rectifying rib 65 also serving as a pump mounting leg at a predetermined pitch along a circumferential direction to a peripheral portion of a bottom plate 62 having a suction cone 60, and connecting a flange 66 to an upper end of the rectifying rib 65. Constituting a pump base 67,
The flange 66 of the pump base 67 and the flange 12a are bolted together to be integrated. Then, a sub flow path forming plate 68 is attached between the flow regulating ribs 65 so as to surround the suction port 14a of the suction bell mouth 14, so that the flow from the water surface to the suction port 14a is reduced. The flow is divided into a main flow F passing below the passage forming plate 68 and a sub flow G passing above.

In this embodiment, the sub-flow path forming plate 68 is mounted directly between the rectifying ribs 65 of the pump base 67 without being directly mounted on the suction bell mouth 14. With this configuration, the sub-channel forming plate 68
In addition to preventing the occurrence of the air suction vortex due to the above, the underwater vortex is also prevented by the suction cone 60, and the swirling flow around the pump can be suppressed by the rectifying rib 65 which also functions as a rectifier, which is excellent overall. Vortex countermeasures. Further, since it is not necessary to directly attach the sub flow path forming plate 68 to the suction bell mouth 14, it is advantageous in terms of structure and cost.

FIG. 18 shows a pump vortex prevention apparatus according to a seventh embodiment of the present invention.
The periphery of the suction port 14a of the suction bell mouth (suction part) 14 connected to the lower end of the cylinder is surrounded by a cylindrical sub-channel forming plate (sub-channel forming body) 70 to form the suction bell mouth 14 and the sub-channel. A sub-flow path 72 extending in a substantially vertical direction is formed between the sub-flow path plate 70 and the suction bell mouth 14 via a rib 74 in which the sub-flow path formation plate 70 is arranged at a predetermined pitch in the circumferential direction.
It is fixed to. The rib 74 is configured such that its upper part protrudes upward from the upper edge of the sub-flow path forming plate 70, and its length (height) is set to be substantially the same as the height of the suction bell mouth 14. Have been.

According to this embodiment, by increasing the length of the rib 74, dust is prevented from being wound around the upper edge of the rib 74, and the upper portion of the rib 74 is exposed in the water tank. Thus, even if a swirling flow R (see FIG. 15) is generated around the pump, it is possible to prevent the air suction vortex and the underwater vortex from being generated by the swirling flow R.

As shown in FIG. 19, a sub-channel forming plate 76 made of a perforated plate may be used instead of the sub-channel forming plate 70 shown in FIG. By using the sub-channel forming plate 76, the weight can be reduced. In addition, although not shown, a short cylindrical sub-channel forming plate may be arranged in a plurality of stages at predetermined intervals.

FIG. 20 shows a pump vortex prevention apparatus according to an eighth embodiment of the present invention.
The suction bell mouth (suction portion) 14 connected to the lower end of the suction bell mouth is provided with a large number of through holes 14c communicating vertically, and a cylindrical sub-flow path forming plate (sub-flow path forming body) is formed at the outer peripheral end of the suction bell mouth 14. ) 80 are connected to form a sub flow path 82 that passes through the inside of the through hole 14c provided in the suction bell mouth 14 from between the outer peripheral surface of the suction bell mouth 14 and the sub flow path forming plate 80. .

According to this embodiment, the sub flow path forming plate 8
A rib for fixing 0 is not required, and the structure can be simplified. In addition, in this example, although the example which provided the circular through-hole 14c in the suction bell mouth 14 is shown,
It goes without saying that a long hole or a rectangular through hole extending in the circumferential direction may be provided.

FIG. 21 shows a pump vortex prevention apparatus according to a ninth embodiment of the present invention.
The periphery of the suction port 14a of the suction bell mouth (suction part) 14 connected to the lower end of the cylinder is surrounded by a cylindrical sub-channel forming plate (sub-channel forming body) 90 to form the suction bell mouth 14 and the sub-channel. A sub-flow passage 92 extending in a substantially vertical direction is formed between the suction bell mouth 14 and the plate 90 via ribs 94 arranged at a predetermined pitch in the circumferential direction.
, And a hollow disk-shaped inflow amount adjusting plate 96 is attached to the upper end of the sub-channel forming plate 90.

According to this embodiment, by adjusting the amount of water flowing into the sub flow passage 92 by the inflow adjusting plate 96, a large amount of water flows into the sub flow passage 92, and The generation of the air suction vortex can be prevented.

FIG. 22 shows a pump vortex prevention apparatus according to a tenth embodiment of the present invention. This apparatus has a support plate 100 mounted on the outer periphery of a discharge bowl (suction portion) 22. Multiple links 1 with one end rotatably connected
A split type sub-flow path forming plate (sub-flow path forming body) 104 is rotatably connected to the other end of the support plate 02, and a stopper 106 for restricting the rotation is attached below the link 102 of the support plate 100. Further, a wire 108 is connected to the sub-channel forming plate 104.

Thus, by pulling the wire 108 upward, each link 102 is swung upward, and the sub-flow path forming plate 104 is moved while being reduced in diameter in a substantially parallel state, and the wire 108 is moved. By loosening, each link 102 is swung downward by its own weight of the sub flow path forming plate 104 to move the sub flow path forming plate 104 while expanding the diameter of the sub flow path forming plate 104 in a substantially parallel state. 10
6, the movement of the discharge bowl 22 is restricted, and the sub flow path 1 is located between the outer peripheral surface of the discharge bowl 22 and the sub flow path forming plate 104.
10 are formed.

According to this embodiment, for example, when countermeasures against vortices are to be taken later, the auxiliary flow path forming plate 104 is attached to the outer periphery of the discharge bowl 22, and the wire 108 is pulled to reduce the diameter of the auxiliary flow path forming plate 104. In this state, the discharge bowl 2 is inserted through the opening 112a of the pump installation base 112.
2 is installed in a closed channel, and after that, the wire 108 is loosened to expand the diameter of the sub flow path forming plate 104 to form the sub flow path 110 between the discharge bowl 22 and the sub flow path forming plate 104. the diameter of the auxiliary flow path forming plate 104 than opening dimension D ₁ of the opening 112a for inserting the discharge bowl 22 discharge bowl 2
2 can be arranged on the outer periphery.

As shown in FIG. 23, for example, the flange 12a of the suction casing 12 and the suction bell mouth 14
The supporting member 120 is fixed between the supporting member 120 and the flange 14b, and the split type sub-channel forming plate 124 is swingably supported by a pivot 122 attached to the supporting member 120. A wire 128 is connected to the end, whereby the wire 128 is pulled upward, thereby swinging the sub-flow path forming plate 124 upward to reduce the diameter thereof.
By loosening the sub flow passage forming plate 124, the sub flow passage forming plate 124 may be swung downward by its own weight to expand the diameter, and may be brought into contact with the stopper 130 to restrict the movement thereof.

[0053]

As described above, according to the present invention,
A vortex countermeasure can be taken by arranging a sub-flow path forming body on the outer periphery of the suction part without taking a countermeasure against vortex by construction of a concrete structure in a conventional pump pit. Need only prepare a square aquarium,
No additional civil engineering costs are required for eddy control. In addition, since the sub-flow path forming body can be easily installed on site, the delivery time is greatly reduced, and the civil engineering cost is significantly reduced.

[Brief description of the drawings]

FIG. 1 shows a main part of a pump vortex prevention device according to a first embodiment of the present invention, where (a) is a side sectional view and (b) is Y in (a).
FIG. 4 is a sectional view taken along line -Y.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a diagram corresponding to FIG. 1B showing a modification of the pump vortex prevention device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing another modified example,
(B) It is an equivalent figure.

FIG. 5 is a side sectional view showing a main part of a pump vortex prevention apparatus showing still another modified example.

FIGS. 6A and 6B show a main part of a pump vortex prevention apparatus according to a second embodiment of the present invention, wherein FIG. 6A is a side sectional view, and FIG.
FIG. 4 is a sectional view taken along line -Y.

FIG. 7 is an enlarged view of a main part of FIG. 6;

FIG. 8 is a view corresponding to FIG. 7, showing a modification of the pump vortex prevention device according to the second embodiment of the present invention.

9A and 9B show another modified example, in which FIG. 9A is a side sectional view, and FIG. 9B is a sectional view taken along line YY of FIG. 9A.

FIG. 10 is a view similar to FIG. 7, showing still another modification.

FIG. 11 is a diagram corresponding to FIG. 7, showing still another modified example.

12A and 12B are diagrams showing still another modified example, in which FIG. 12A is a side sectional view, and FIG. 12B is a sectional view taken along line YY of FIG. 12A.

13A and 13B show a main part of a pump vortex prevention device according to a third embodiment of the present invention, wherein FIG. 13A is a side sectional view and FIG. 13B is a plan view.

14 (a) and 14 (b) show an example corresponding to an operation in a state where the water level is low, in which FIG. 14 (a) is a side sectional view and FIG. 14 (b) is a plan view.

15A and 15B show a main part of a pump vortex prevention device according to a fourth embodiment of the present invention, wherein FIG. 15A is a side sectional view, and FIG. 15B is a sectional view taken along line YY of FIG.

16A and 16B show a main part of a pump vortex prevention device according to a fifth embodiment of the present invention, wherein FIG. 16A is a side sectional view, and FIG. 16B is a sectional view taken along line YY of FIG.

17A and 17B show a modification of the pump vortex prevention device according to the sixth embodiment of the present invention, wherein FIG. 17A is a side sectional view, and FIG.
5 is a sectional view taken along line YY of FIG.

FIGS. 18A and 18B show a main part of a pump vortex prevention device according to a seventh embodiment of the present invention, wherein FIG. 18A is a side sectional view, and FIG. 18B is a sectional view taken along line YY of FIG.

FIG. 19 is a view corresponding to FIG. 18A showing a modification of the pump vortex prevention device according to the seventh embodiment of the present invention.

FIGS. 20A and 20B show a main part of a pump vortex prevention device according to an eighth embodiment of the present invention, wherein FIG. 20A is a side sectional view, and FIG. 20B is a sectional view taken along line YY of FIG.

FIGS. 21A and 21B show a main part of a pump vortex prevention device according to a ninth embodiment of the present invention, wherein FIG. 21A is a side sectional view, and FIG.

FIGS. 22A and 22B show a main part of a pump vortex prevention device according to a tenth embodiment of the present invention, wherein FIG. 22A is a side sectional view, and FIG. 22B is a plan view of a split type sub-channel forming plate.

FIG. 23 is a side sectional view showing a main part of a modification of the pump vortex prevention device according to the tenth embodiment of the present invention.

24 shows a state in which a drainage pump is installed in a conventional open channel, (a) is a side sectional view, and (b) is a plan view.

25 (a) is a side sectional view and FIG. 25 (b) is a plan view showing a conventional example in which a vortex countermeasure is applied to the open channel shown in FIG. 24.

26 (a) is a side view, and FIG. 26 (b) is a bottom view of FIG. 26 (a).

FIG. 27 is a diagram attached to an explanation of its operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Pump pit 12 Suction casing (pump casing) 14 Suction bell mouth (suction part) 14a Suction port 22 Discharge bowl 24, 24a, 24b, 44, 44a Suction bell mouth structure 26, 42, 64, 74, 94, 126 rib 28, 32, 34, 36, 40, 68, 70, 76, 8
0, 90, 104, 124 Sub flow path forming plate (sub flow path forming body) 30, 46, 72, 82, 92, 110 Sub flow path 38 Pipe (sub flow path forming body) 48 Guide 52 Preventing upper swirl flow Plate 54 Lower swirl prevention plate 65 Rectifier rib 67 Pump frame 96 Inflow control plate 100 Support plate 102 Link 106, 130 Stopper 108, 128 Wire 120 Support 122 Axis F Main flow G Sub flow LWL Minimum water level R Swirling flow V Channel flow velocity

Continuing on the front page (72) Inventor Tsuyoshi Tomita 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Corporation (72) Inventor Hiroyuki Kato 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Inside Ebara Corporation

Claims (5)

[Claims] 1. A sub-flow path forming body, which forms a sub-flow path with a gap formed between the outer peripheral surface of a suction portion and an outer peripheral surface of the suction portion having a suction port installed in an open channel, is substantially concentric. A vortex prevention device for a pump, characterized in that the device is arranged in a pump. 2. The pump vortex prevention device according to claim 1, wherein the sub-flow path forming body is disposed substantially horizontally at a position separated from the suction port of the suction section by a predetermined distance. apparatus. 3. The pump according to claim 1, wherein the sub-flow path forming body is formed in a substantially cylindrical shape, and is arranged so as to surround the suction portion with a predetermined space therebetween. Eddy prevention device. 4. The pump vortex prevention device according to claim 1, wherein a plate-like object for preventing surface vortex generation is provided above the suction port of the sub-flow path forming body. 5. The pump vortex prevention device according to claim 1, wherein a swirl flow prevention plate is attached to the sub-flow path forming body.