JPH11148499A - Vertical pump installed in pre-rotation type suction channel - Google Patents

Abstract

(57) [Summary] [Purpose] Avoiding the use of impellers that need to be newly designed and manufactured, the use of existing impellers prevents the occurrence of peeling, turbulence in the flow, and loss in the suction port. Increase,
Occurrence of overload and vibration due to collision of the flow can be avoided,
The damage is surely prevented. A plurality of flow straightening plates are provided on an inner surface of a suction port on an upstream side of an impeller in a vertical shaft pump into which a pre-swirling flow is introduced. These current plates 12, 12,...
It has an inflow end 12A facing the pre-swirling flow Y1 along the swirling direction of the pre-swirling flow Y1, and an outflow end 12B facing the inlet 4A of the impeller 4 along the axis C of the impeller 4. Then, the pre-swirling flow Y1 introduced from the inflow end 12A is gradually changed from the swirling flow to the axial flow YC along the axis C direction of the impeller 4, and is guided to the outflow end 12B. The direction change part 12R is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical shaft pump installed in a pre-swirl type suction channel, and in particular, converts water introduced into a suction port upstream of an impeller into a flow in an axial direction while pre-swirl. The present invention relates to a vertical shaft pump having a function capable of guiding to an inlet of an impeller.

[0002]

2. Description of the Related Art The applicant of the present invention has proposed a pre-rotation type suction channel suitable as a suction channel for a large vertical pump for rainwater drainage and irrigation in Japanese Patent Application Laid-Open No. Hei 8-109893. As shown in FIGS. 4 and 5, the pre-swirl type suction channel has a ceiling 6, a bottom 8, and side walls 7A and 7B on both sides.
A vertical cross-section suction hole 3 communicating with the suction port 2 of the vertical shaft pump 1 is formed in the ceiling 6 so as to face the suction hole 3 and has a small diameter section. A frusto-conical ridge 9 is erected on the bottom 8, and extends through the suction port 2, the suction hole 3 and the center P of the ridge 9 in the direction of water flow.
Deeper than a second center line C2 orthogonal to the center line C1 of
A standing wall 5 is provided which is continuous with the ceiling part 6, the bottom part 8 and the side walls 7A, 7B on both sides, and the upstream end of the standing wall 5 in one area of the first center line C1 and the downstream end of the one side wall 7A are formed in the first center line C1. 1, a tongue 10 bulging in an arc shape and merging at the tip 10A is formed, and the tip 10A of the tongue 10 is formed.
Is set at a position immediately upstream of the suction hole 3 on the first center line C1, and is located on the upstream end of the standing wall 5 in the other area of the first center line C1, that is, on the second center line C2. From the boundary between the standing wall 5 and the other side wall 7B, the tip 10 of the tongue 10
A, the radius of curvature of the inner surface of the standing wall 5 reaching A
To the second center line C
The cross-sectional area of the arc-shaped flow path 11 formed between the frusto-conical raised portion 9 and the upright wall 5 at a position deeper than 2 is reduced steplessly.

[0003] In the pre-swirl type suction channel of the vertical shaft pump configured as described above, the flow of water is controlled by the vertical wall 5 of the arc-shaped channel 11.
Along the tongue 10 along the inner surface of the tongue, it rises spirally along the frusto-conical ridge 9 while pre-turning in one direction (the same direction as the direction of rotation of the impeller 4) and passes through the suction hole 3. Since it is sucked into the vertical shaft pump 1 from the suction port 2, a sudden change in direction upward can be avoided, and the loss in the suction hole 3 can be reduced. In addition, since there is no flow in the reverse direction on the back side of the second center line C2, the loss before being sucked into the suction hole 3 is also reduced.
Furthermore, since the cross-sectional area of the arc-shaped flow path 11 is reduced steplessly, the flow velocity here gradually increases, and it is possible to avoid an increase in flow clearance and loss caused by a sudden change in the flow velocity. Moreover, since water can be sucked substantially evenly from the entire circumference of the suction hole 3, the imbalance of the suction is eliminated, and the generation of the "stagnation portion" can be suppressed and the generation of the underwater vortex can be suppressed. . Furthermore, since the flow velocity can be increased by reducing the width of the suction channel, a number of excellent effects can be achieved, such as downsizing of the suction channel.

Incidentally, the impeller 4 of the vertical shaft pump 1 is usually used.
Means that the axial flow along the axis C of the impeller 4
It is designed based on the prerequisites guided by Therefore, FIG.
As shown in FIG. 7, a plurality of (for example, four) rectifying plates 12, 12...
In many cases, the pre-swirling flow is turned to an axial flow along the direction of the axis C of the impeller 4 and guided to the inlet 4A of the impeller 4.

However, a vertical pump 1 installed in a pre-swirl type suction water channel configured to introduce a pre-swirl flow in the suction hole 3 and the suction port 2 in the same direction as the rotation direction of the impeller 4.
8, the pre-swirling flow obliquely flows into the flow straightening plates 12, 12,... As shown by an arrow Y1 in FIG. Therefore, when the straightening plates 12, 12,... Extending straight up and down as shown in FIGS. 6 and 7 are provided, the straightening plates 12, 1,.
In the back surface of the inflow end portion 12A in 2.
The flow does not follow the flow path 2, 12,..., But is separated from the flow straightening plates 12, 12,... As shown by the arrow Y2, and the flow-off ends 12 of the flow straightening plates 12, 12,.
A vortex as shown by an arrow Y3 is generated in the stagnation portion between A and disturbs the flow downstream of the dispensing portion. As a result, the loss in the suction port 2 increases, and an overload or vibration due to the collision of the flow occurs, and the flow straightening plates 12 and 1 are generated.
2 ... may be damaged.

For this reason, in the vertical shaft pump 1 installed in the pre-swirl type suction water channel, the use of the straightening plates 12, 12,... Is omitted, and the impeller 4 is operated under the precondition that the pre-swirl flow is guided to the inlet 4A. It is conceivable to design. But in this case,
The existing impeller 4 cannot be used as it is, and a complicated operation for newly designing and manufacturing the impeller 4 matching the pre-rotation type suction channel is required.

[0007]

SUMMARY OF THE INVENTION In a vertical shaft pump installed in a pre-swirl type suction water channel, the use of an impeller, which must be newly designed and manufactured under the precondition that the pre-swirl flow is guided to the inlet, is avoided. If a straightening plate extending straight in the vertical direction is provided on the inner surface of the suction port in order to enable the use of the existing impeller, a brush will be formed on the back surface of the inflow end of the straightening plate, and the downstream of the brush portion will be generated. The flow on the side is disturbed, the loss in the suction port increases, and the flow straightening plate may be damaged by overload or vibration due to the collision of the flow. Therefore, the present invention avoids the use of an impeller that needs to be newly designed and manufactured under the precondition that the pre-swirling flow is guided to the inlet, and the occurrence of peeling is prevented even when using an existing impeller, The flow turbulence and the increase in loss in the suction port caused by the turbulence of the flow are avoided, and the occurrence of overload or vibration due to the collision of the flow is avoided, so that the rectifying plate can be reliably prevented from being damaged. An object of the present invention is to provide a vertical pump installed in a pre-swirl type suction water channel.

[0008]

In order to achieve the above object, a vertical shaft pump installed in a pre-swirl type suction channel according to the present invention comprises a pre-swirl type pump configured to generate a pre-swirl flow in one direction. In a vertical shaft pump installed in a suction channel, an inlet end facing a pre-swirl flow along a swirling direction of the pre-swirl flow, on an inner surface of a suction port on an upstream side of an impeller of the vertical pump in which the pre-swirl flow is introduced. An outflow end portion facing the inlet of the impeller along the axial direction of the impeller, and the pre-swirl flow introduced from the inflow end portion is gradually changed from the flow in the swirling direction in the axial direction of the impeller. And a flow straightening portion provided with an arc-shaped direction changing portion for changing the direction of the flow in the axial direction and guiding the flow to the outflow end.

According to the present invention, since the inflow end of the flow straightening plate faces the pre-swirl flow along the swirling direction of the pre-swirl flow,
The pre-swirling flow flows along the front and back surfaces of the inflow end portion of the flow straightening plate without being separated, and is gradually changed to an axial flow along the axial direction of the impeller by an arc-shaped turning portion. The fluid flows out from the outflow end portion facing the inlet of the impeller along the axial direction of the impeller, flows out and is introduced into the inlet of the impeller.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. 1 is a longitudinal side view, and FIG. 2 is FIG.
3 is a sectional view taken along line AA of FIG. The same or corresponding parts as those in the conventional example described with reference to FIGS. 4 to 7 are denoted by the same reference numerals, and detailed description is omitted. In FIGS. 1 and 2, the suction port 2 on the upstream side of the impeller 4 of the vertical shaft pump 1 is shown.
On the inner surface of a plurality of (for example, four) at equal intervals in the circumferential direction
Are provided.

Each of the impellers 12, 12,... Has an inflow end 12A facing the pre-swirling flow Y1 along the swirling direction of the pre-swirling flow Y1, and an impeller 4, as shown in FIG. An outflow end 12B facing the inlet 4A of the impeller 4 along the axis C direction, and the pre-swirl flow Y1 introduced from the inflow end 12A is gradually changed from the flow in the swirl direction.
And a two-dimensional guide vane provided with an arc-shaped turning portion 12R having a relatively large radius of curvature R for turning to the flow YC in the axial direction along the direction of the axis C and leading to the outflow end portion 12B.

In the above configuration, each of the current plates 12, 12,...
Are opposed to the pre-swirl flow Y1 along the swirling direction of the pre-swirl flow Y1, so that the pre-swirl flow Y1 flows in along the inflow ends 12A of the flow straightening plates 12, 12,. I do. For this reason, like the conventional current plate 12, 12,.
No scuffing occurs on the back surface of the inflow end portion 12A, and after flowing along the front and back surfaces of the inflow end portion 12A,
The arc-shaped direction changing portion 12R gradually changes the flow to an axial flow YC along the axis C of the impeller 4, and faces the inlet 4A of the impeller 4 along the axis C of the impeller 4. The flow YC flows out from the outflow end portion 12B in the axial direction and flows out into the inlet 4A of the impeller 4.

As described above, the pre-swirling flow Y1 can be converted into the axial flow YC and flown out without being dislodged and introduced into the impeller 4, so that the conventional flow straightening plates 12, 12,. The stagnation and eddy current Y3 observed in ... are not generated at all. Therefore, since the flow disturbance is eliminated, the loss in the suction port 2 caused by the flow disturbance is prevented from increasing, and the occurrence of overload or vibration due to the collision of the flow is prevented, so that the rectifying plates 12, 12 are prevented. .. Can be reliably prevented. As a result, it is possible to use the existing impeller 4 while avoiding the use of an impeller that needs to be newly designed and manufactured under the precondition that the pre-swirl flow is introduced to the inlet. The complicated work of newly designing and manufacturing the impeller 4 under the prerequisites is unnecessary.

In this embodiment, four rectifying plates 12, 12,... Are provided, but the rectifying plates 12, 12,.
Is not limited to four and is optional. Further, although the two-dimensional guide blade is used, the present invention is not limited to the two-dimensional guide blade, and a three-dimensional guide blade may be used.

[0015]

As described above, according to the present invention, the inflow end of the current plate is opposed to the pre-swirling flow along the swirling direction of the pre-swirling flow. After flowing without removing along the front and back surfaces of the part, the direction is gradually changed to the axial flow along the axial direction of the impeller by the arc-shaped turning part, and along the axial direction of the impeller. It flows out as an axial flow from the outflow end portion facing the inlet of the impeller, and is introduced into the inlet of the impeller. For this reason, unlike the conventional current plate, no scuffing occurs on the back surface of the inflow end portion, and after flowing along both the front and back surfaces of the inflow end portion, the arc-shaped direction changing portion gradually turns the impeller. The air flow is changed to an axial flow along the axial direction, and flows out in the axial direction from the outflow end portion facing the inlet of the impeller along the axial direction of the impeller to flow out and is introduced into the inlet of the impeller. Therefore, there is no stagnation or eddy current observed in the conventional current plate. Therefore, since the flow disturbance is eliminated, the loss in the suction port 2 caused by the flow disturbance is prevented from increasing, and the occurrence of overload or vibration due to the collision of the flow is prevented. It can be reliably prevented. As a result, it is possible to use the existing impeller, avoiding the use of an impeller that needs to be newly designed and manufactured under the precondition that the pre-swirling flow is guided to the inlet. The complicated work of newly designing and manufacturing an impeller under the condition becomes unnecessary.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional side view taken along line AA of FIG. 1;

FIG. 3 is an explanatory diagram showing an embodiment of a current plate according to the present invention in an enlarged manner.

FIG. 4 is a cross-sectional plan view of a suction channel.

FIG. 5 is a vertical sectional side view taken along line BB of FIG. 4;

FIG. 6 is a side view of a conventional vertical pump provided with a current plate.

FIG. 7 is a vertical sectional side view taken along line CC of FIG. 6;

FIG. 8 is an enlarged view illustrating a conventional current plate.

[Explanation of symbols]

 Reference Signs List 1 Vertical shaft pump 2 Vertical shaft pump suction port 4 Impeller 4A Impeller inlet 12 Rectifier plate 12A Inflow end 12B Outflow end 12R Arc-shaped turning portion C Impeller axis Y1 Pre-rotational flow YC Flow in axial direction

Claims (1)

[Claims] 1. A vertical shaft pump installed in a pre-swirl type suction water channel configured to generate a unidirectional pre-swirl flow, wherein an inner surface of a suction port on an upstream side of an impeller of the vertical shaft pump into which the pre-swirl flow is introduced. An inflow end facing the pre-swirling flow along the swirling direction of the pre-swirling flow; and an outflow end facing the inlet of the impeller along the axial direction of the impeller. A rectifying plate having an arc-shaped diverting portion that gradually turns the pre-swirling flow introduced from the whirl direction flow into an axial flow along the axial direction of the impeller and guides the flow to the outflow end portion is provided. A vertical shaft pump installed in a pre-swirl type suction channel provided.