JP2807851B2 - Vertical pump suction channel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water suction passage of a vertical shaft pump, and more particularly to a water suction passage of a large capacity vertical shaft pump for rainwater drainage and irrigation.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show known water suction passages of a vertical shaft pump of this type. This water intake channel 1
Is constructed by concrete, and both side walls 2A,
2A, the downstream end of both side walls 2A, 2A has a tunnel type structure provided with a standing wall 3 and a ceiling portion 4 which form the end position E of the water suction channel 1 by merging. An annular bulging portion 10 bulging downward around the suction hole 9 communicating with the inlet 8 of the casing 7 accommodating the impeller 6 of the vertical shaft pump 5.
Are formed continuously on the lower surface of the ceiling portion 4. Ceiling 4
Is inclined by a gentle downward gradient from the upstream side of the water suction passage 1 to the immediately upstream position P of the annular bulging portion 10 and is formed horizontally from the immediately upstream position P to the terminal position E. Also, the radially outer bulging start end 10a of the annular bulging portion 10
Is set on a circular trajectory 11 drawn on the projection plane with a radius R from the center O of the suction hole 9, and the outer surface 10A extending from the radially outer bulging start end 10a to the bulging lowermost end 10b.
Is uniformly formed in the circumferential direction by a slope inclined at a predetermined downward inclination angle θ1, and a curved surface which rises in a bell shape from an inner surface 10B from a lowermost bulging end 10b to a radially inner bulging end 10c. It is formed uniformly in the circumferential direction. Further, a truncated conical raised portion 13 is formed at the bottom 12 of the water suction channel 1 so as to face below the suction hole 9.

The suction hole 9 and the annular bulge 10
In the water suction channel 1 having the above-mentioned condition, the separation of the flow, the drift or the secondary flow, etc. are suppressed, the water is sucked as uniformly as possible from all the circumferences of the suction port 9 , and the load of the impeller 6 is made equal all the way around the pump. In order to achieve the stability of the pump and to improve the pump efficiency, the distance L from the center O of the suction hole 9 to the end position E of the water suction passage 1 is set to the distance L1 from the center O of the suction hole 9 to the side walls 2A, 2A.
The structure is set smaller than that. That is, when the upright wall 3 is formed, for example, in a semicircular shape on the projection plane, the center O1 of the radius of curvature R1 forming the upright wall 3 is slightly eccentric to the upstream side of the water suction passage 1 from the center O of the suction hole 9. It is designed so that the cross-sectional area of the outer surface 10A of the downstream portion of the annular bulging portion 10 and the rear passage 14 surrounded by the ceiling portion 4 and the standing wall 3 is gradually reduced from both side walls 2A, 2A to the terminal position E. It has a structure.

However, in the conventional water suction channel 1, since the lower surface of the ceiling portion 4 is formed horizontally from a position immediately upstream of the annular bulging portion 10 to a terminal position E, the annular bulging portion 10 is formed.
Between the lower surface of the ceiling part 4 and the bottom part 12 of the water absorption channel 1
The height of the rear half of the formed annular passage is uniform .
The cross-sectional area of the rear passage 14 is smaller than that of the side walls 2A, 2A.
A gradual reduction from A to the end position E does not make it possible to evenly suck water from the entire circumference of the suction hole 9 with uniform flow distribution and flow distribution. As a result, the impeller 6
However, there is a problem that the load fluctuates in the circumferential direction to make the pump operation state unstable and lower the pump efficiency.

[0005]

The problem to be solved is that the ceiling of the water intake passage is formed horizontally from the position immediately upstream of the annular bulging portion to the terminal position, so that the flow rate distribution and the flow rate distribution of water are made. Since it is not possible to uniformly suction water from the entire circumference of the suction hole, the load of the impeller fluctuates in the circumferential direction, making the pump operation state unstable and lowering the pump efficiency.

[0006]

SUMMARY OF THE INVENTION The present invention has a suction hole communicating with an inlet of a suction casing of a vertical shaft pump, and an annular bulging portion surrounding the suction hole and bulging downward. In the water intake passage of the vertical shaft pump, the ceiling portion of the water intake passage is formed so as to be inclined with a downward gradient from an upstream position of the annular bulging portion to a downstream end position of the annular bulging portion, so that a cross-sectional area of the flow passage is reduced.
From a position immediately upstream of the annular bulge to a downstream end of the annular bulge
It is characterized by a structure that is gradually reduced to the end position, so that water flow distribution and flow velocity distribution are evenly distributed so that water is sucked evenly from the entire circumference of the suction hole, stabilizing the pump operation state and improving pump efficiency Achieved the purpose of achieving.

[0007]

According to the present invention, the ceiling is formed so as to have a downward gradient from the upstream position of the annular bulging portion to the terminal position downstream of the annular bulging portion, so that the cross-sectional area of the flow path of the annular bulging portion is reduced . Immediately upstream
Gradually from the position to the downstream end position of the annular bulge
Be to, I that the flow rate in this portion is gradually increased
Ri can be sucked evenly water from the entire circumference of the suction hole to equalize flow distribution and flow rate distribution.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a water intake channel according to the present invention, and FIG.
3 is a vertical sectional side view of an air line shown in FIG. The same or corresponding parts as those in the conventional example are denoted by the same reference numerals, and detailed description is omitted. In these figures, the ceiling 4 of the water intake channel 1
The lower surface slopes down from the position immediately upstream of the annular bulge 10 to the end position E immediately downstream of the annular bulge 10.
Then , the cross-sectional area of the flow path is adjusted to the position immediately upstream of the annular bulging portion 10.
From P to the downstream end position E of the annular bulge 10 gradually.
The structure is reduced .

As described above, the lower surface of the ceiling portion 4 is formed so as to be inclined with a downward gradient from a position immediately upstream of the annular bulging portion 10 to a terminal position E immediately downstream of the annular bulging portion 10 to form a cross-sectional area of the flow passage. Is gradually reduced, so that the flow velocity of the water is gradually increased here, and the water flow can be uniformly sucked from the entire circumference of the suction hole 9 by making the flow distribution and the flow velocity distribution uniform. Therefore, the load of the impeller 6 can be made uniform over the entire circumference to stabilize the pump operation state and improve the pump efficiency.

[0010]

As described above, according to the present invention, the ceiling
The lower surface of is formed with a downward slope from the upstream position of the annular bulging portion to the terminal position downstream of the annular bulging portion, so that the cross-sectional area of the flow path is gradually reduced, so that the <br/> Since the flow velocity can be gradually increased , the water flow distribution and the flow velocity distribution can be evenly distributed so that water can be uniformly sucked from the entire circumference of the suction hole. the suction of equal water, to stabilize the pump operation state by the load of the impeller the entire circumference equally, and it is possible to improve the pump efficiency.

[Brief description of the drawings]

FIG. 1 is a plan view of a water suction channel according to the present invention.

FIG. 2 is a vertical sectional side view of an air line in FIG. 1;

FIG. 3 is a plan view of a conventional water suction passage.

FIG. 4 is a vertical sectional side view taken along the line II in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water absorption channel 4 Ceiling portion of water absorption channel 5 Vertical shaft pump 7 Suction casing 8 Inlet of suction casing 9 Suction hole 10 Annular bulging part P Upstream position of annular bulging part E Terminal position

Claims (1)

(57) [Claims] 1. A vertical shaft pump having a suction hole communicating with an inlet of a suction casing of a vertical shaft pump and an annular bulging portion surrounding the suction hole and bulging downward. The lower surface of the ceiling portion of the water suction passage is formed so as to be inclined with a downward gradient from the upstream position of the annular bulging portion to the downstream end position of the annular bulging portion, so that the cross-sectional area of the flow path is just above the annular bulging portion.
Gradual contraction from the flow position to the downstream end position of the annular bulge
A vertical pump water suction passage having a reduced configuration .